Title of Invention

PHARMACEUTICAL COMPOSITION FOR THE TREATMENT OF CNS-RELATED CONDITIONS

Abstract The present invention provides novel methods and compositions for the treatment and prevention of CNS-related conditions. One of the CNS-related conditions treated by the methods and compositions of the invention is Alzheimer"s disease.
Full Text THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION (NATIONAL PHASE)
(See Section 10, Rule 13)
TITLE
METHODS AND COMPOSITIONS FOR THE TREATMENT OF CNS-RELATED CONDITIONS"
APPLICANT
ADAMAS PHARMACEUTICALS
1900 Powell Street, Suite 1050,
Emeryville,
California 94608, USA
The following specification describes the invention

METHODS AND COMPOSITIONS FOR THE TREATMENT OF CNS-RELATED
CONDITIONS
FIELD OF THE INVENTION
This invention relates to methods and compositions for treating CNS-related conditions, such as Alzheimer's disease.
BACKGROUND OF THE INVENTION
Acute and chronic neurological and neuropsychiatric diseases are among the leading
causes of death, disability, and economic expense in the world. Presently, Alzheimer's disease is the fourth leading cause of death in the USA. Today there is no known cure for this chronic degenerative ailment, which directly affects millions of people throughout the world. Other diseases and disorders of the central nervous system also result in substantial suffering and cost for those afflicted by the ailments as well as their families and providers.
Numerous drugs exist in the market today to treat the symptoms or manage the progression of these diseases, but most have modest or limited efficacy. Frequently, polypharmacy is employed to optimize therapy to the specific needs of patients at different stages of the disease. One of the key challenges in treating these disorders is the high degree of interplay amongst the pathways that control both normal and abnormal neuronal functions. The therapeutic management of these functions is typically determined such that the therapeutic effects are maximized while minimizing the debilitating side effects of the therapies. This effort is usually more complex when multiple therapeutics are employed. Improved therapeutics for treatment of these diseases and disorders are needed.
SUMMARY OF THE INVENTION
In general, the present invention provides methods and compositions for treating and preventing CNS-related conditions, such as neurodegenerative conditions (e.g., Alzheimer's


disease and Parkinson's disease) and pain, by administering to a subject in need thereof a combination that includes an N-Methyl-D-Aspartate receptor (NMDAr) antagonist and a second agent such as acetylcholinesterase inhibitor (AChel). The administration of the combinations described herein results in the alleviation and prevention of symptoms associated with or arising from CNS-related conditions such as Parkinson's disease or
Alzheimer's disease including, for example, loss of memory, loss of balance, hallucinations, delusions, agitation, withdrawal, depression, communication problems, cognitive loss, personality change, confusion and insomnia. The combinations of the present invention may be used in the prevention or treatment of CNS-related conditions associated with Alzheimer's
disease and may also be helpful for the treatment and prevention of headaches,
cerebrovascular diseases, motor neuron diseases, dementias, neurodegenerative diseases, strokes, movement disorders, ataxic syndromes, disorders of the sympathetic nervous system, cranial nerve disorders, myelopathies, traumatic brain and spinal cord injuries, radiation brain injuries, multiple sclerosis, post-meningitis syndrome, prion diseases, myelitic disorders,
radiculitis, neuropathies, pain syndromes, axonic brain damage, encephalopathies, chronic fatigue syndrome, psychiatric disorders, glucose dysregulation, and drug dependence.
The NMDAr antagonist, the AChel, or both agents may be administered in an amount similar to that typically administered to subjects. Optionally, the amount of the NMDAr antagonist, the AChel, or both agents may be administered in an amount greater than or less
than the amount that is typically administered to subjects. If desired, the amount of the NMDAr antagonist in the pharmaceutical composition is less than the amount of NMDAr antagonist required in a unit dose to obtain the same therapeutic effect for treating or preventing a CNS-related condition when the NMDAr antagonist is administered in the absence of the AChel. Alternatively, the amount of the AChel in the pharmaceutical
composition is less than the amount of the AChel required in a unit dose to obtain the same therapeutic effect for treating or preventing a CNS-related condition when the AChel is administered in the absence of the NMDAr antagonist. Optionally, the NMDAr antagonist, the AChel, or both are present at a higher dose than that typically administered to a subject for a specific condition. For example, the amount of memantine (an NMDAr antagonist)
required to positively affect the patient response (inclusive of adverse effects) may be 2.5-80 mg per day rather than the typical 10-20 mg per day administered for presently approved indications i.e. without the improved formulations described herein. A higher dose amount of the NMDAr antagonist in the present invention may be employed whereas a lower dose of


the NMDAr antagonist may be sufficient when combined with the AChel to achieve a therapeutic effect in the patient. Optionally, lower or reduced amounts of both the NMDAr antagonist and the AChel are used in a unit dose relative to the amount of each agent when administered as a monotherapy. In a preferred embodiment, the amount of the NMDAr antagonist in the pharmaceutical composition is equal to or greater than the amount typically administered to a subject for a specific condition as a monotherapy and the amount of the AChel in the pharmaceutical composition is less than the amount typically administered to a subject for a similar condition.
The invention also provides a pharmaceutical composition that includes an NMDAr
antagonist and an AChel. Optionally, a pharmaceutically acceptable carrier is included.
Although compositions comprising a NMDAr antagonist and a second agent such as acetylcholinesterase inhibitor (AChel) have been disclosed (e.g. US 2004/0087658), the problem of providing release of the NMDAr antagonist in a desired manner (e.g. in an amount high enough to treat symptoms or damaging effects of an underlying disease while
avoiding undesirable side effects e.g. CNS side effects) when present as a combined therapy has not been addressed. In particular, the presently available dosage forms of NMDAr antagonists need to be administered frequently and require dose escalation at the initiation of therapy to avoid side effects associated with initial exposure to the therapeutic agent. This leads to difficulty in achieving adequate patient compliance, which is further exacerbated by
the complicated dosing schedules of therapeutic modalities used for neurological or
neuropsychiatric disorders. This problem has not been addressed in the context of providing an NMDAr antagonist as a combined therapy.
Providing a NMDAr antagonist in combination with an AChel requires careful formulation and the pharmacokinetic properties of the two agents will need to be taken into
account, for instance to ensure that the amount and rate of release of each of the agents is sufficient for a therapeutic benefit whilst minimizing or avoiding undesired side effects. Further, not only do the pharmacokinetic properties of each of the drugs (e.g. Tmax, drug half-life etc.) need to be considered, but any interaction between the two agents is a further complicating factor.
In one embodiment of the invention, the NMDAr antagonist, the AChel, or both
agents may be provided in a controlled or extended release form with or without an immediate release component in order to maximize the therapeutic benefit of each, while reducing unwanted side effects associated with each.


As used herein, "immediate release formulation" refers to a formulation of an active pharmaceutical ingredient that releases greater than 80 percent of the active pharmaceutical ingredient in less than one hour in a USP dissolution method as described herein or by the manufacturer for a commercial product. Typically, the release of the active ingredient in an immediate release formulation is greater than 80 percent in less than 30 minutes as in Figures l A and 2 A.
When these drugs are provided in an oral form without the benefit of controlled or extended release components, they are released and transported into the body fluids over a period of minutes to several hours. Thus, the composition of the invention may contain an
NMDAr antagonist and a sustained release component, such as a coated sustained release matrix, a sustained release matrix, or a sustained release bead matrix. In one example, memantine (e.g., 5-80 mg) is formulated without an immediate release component using a polymer matrix (e.g., Eudragit), Hydroxypropyl methyl cellulose (HPMC) and a polymer coating (e.g., Eudragit). Such formulations are comprsessed into solid tablets or granules.
Optionally, a coating such as Opadry® or Surelease® is used.
As used herein the terms "extended release dosage form", "controlled release dosage form" and "sustained release dosage form" and like expressions are used interchangeably and include dosage forms where the active drug substance or substances are released over an extended period of time. The term "extended" release should be understood in contrast to
immediate release and, in particular, the term indicates that the formulation does not release the full dose of the active ingredient immediately after dosing. Such extended release dosage forms typically allow a reduction in dosing frequency as compared to that presented by a conventional dosage form such as a solution or an immediate release dosage form. The extended release forms may or may not comprise an immediate release component.
Optionally, the composition described herein is formulated such that at least one of
said NMDAr antagonist or said AChel has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
As used herein, "C" refers to the concentration of an active pharmaceutical ingredient
in a biological sample, such as a patient sample (e.g. blood, serum, and cerebrospinal fluid). The concentration of the drug in the biological sample may be determined by any standard assay method known in the art. The term "Cmax" refers to the maximum concentration


reached by a given dose of drug in a biological sample. The term "Cmean" refers to the average concentration of the drug in the sample over time. Cmax and Cmean may be further defined to refer to specific time periods relative to administration of the drug. The time required to reach the maximal concentration ("Cmax") in a particular patient sample type is referred to as the "Tmax." The agents of the combination are administered in formulations that reduce the variability of the ratio of the concentrations of the active agents over a period of time, thereby maximizing the therapeutic benefit while minimizing the side effects.
In a preferred embodiment, the dosage form is provided in a non-dose escalating, twice per day or once per day form. In such cases, the concentration ramp (or Tmax effect)
may be reduced so that the change in concentration as a function of time (dC/dT) is altered to reduce or eliminate the need to dose escalate the drug. A reduction in dC/dT may be accomplished, for example, by increasing the Tmax in a relatively proportional manner. Accordingly, a two-fold increase in the Tmax value may reduce dC/dT by approximately a factor of 2. Thus, the NMDAr antagonist may be provided so that it is released at a rate that
is significantly reduced over an immediate release (so called IR) dosage form, with an
associated delay in the Tmax. The pharmaceutical composition may be formulated to provide a shift in Tmax by 24 hours, 16 hours, 8 hours, 4 hours, 2 hours, or at least 1 hour. The associated reduction in dC/dT may be by a factor of approximately 0.05, 0.10, 0.25, 0.5, or at least 0.8. In certain embodiments, this is accomplished by releasing less than 30%, 50%,
75%, 90%, or 95% of the NMDAr antagonist into the circulatory or neural system within one hour of such administration.
The provision of such non-dose escalating dosage forms are particularly useful as they provide the drug at a therapeutically effective amount from the onset of therapy further improving patient compliance and adherence and enable the achievement of a therapeutically
effective steady-state concentration of the drug in a shorter period of time. This results in an earlier indication of effectiveness and increasing the utility of these therapeutic agents for diseases and conditions where time is of the essence. Furthermore, the compositions of the present invention, by virtue of their design, allow for higher doses of the drug to be safely administered, again increasing the utility of these agents for a variety of indications.
If desired, the NMDAr antagonist or the AChel of the combination is released into a
subject sample at a slower rate than observed for an immediate release (IR) formulation of the same quantity of the antagonist. The release rate is measured as the dC/dT over a defined period within the period of 0 to Tmax for the IR formulation and the dC/dT rate is less than


about 80% of the rate for the IR formulation. In some embodiments, the dC/dT rate is less than about 60%, 50%, 40%, 30%, 20%.or 10% of the rate for the IR formulation. Similarly, the AChel may also be released into a patient sample at a slower rate than observed for an IR formulation of the same quantity wherein the release rate is measured as the dC/dT over a defined period within the period of 0 to Tmax for the IR formulation and the dC/dT rate is less than about 80%, 60%, 50%, 40%, 30%, 20%, or 10%, of the rate for the IR formulation of the same NMDAr antagonist over the first 1, 2, 4, 6, 8, 10, or 12 hours.
Optionally, the sustained release formulations exhibit plasma concentration curves having initial (e.g., from 2 hours after administration to 4 hours after administration) slopes
less than 75%, 50%, 40%, 30%, 20% or 10% of those for an IR formulation of the same dosage of the same NMDAr antagonist. The precise slope for a given individual will vary according to the NMDAr antagonist being used, the quantity delivered, or other factors, including, for some active pharmaceutical agents, whether the patient has eaten or not. For other doses, e.g., those mentioned above, the slopes vary directly in relationship to dose.
Using the sustained release formulations described herein, the NMDAr antagonist or
the AChel reaches a therapeutically effective steady state plasma concentration in a subject within the course of the first five, seven, nine, ten, twelve, fifteen, or twenty days of administration. For example, the formulations described herein, when administered at a substantially constant daily dose (e.g., memantine at a dose ranging between 15 mg and 80
mg and preferably between 20 and 45 mg) may reach a steady state plasma concentration in approximately 70%, 60%, 50%, 40%, 30%, or less of the time required to reach such plasma concentration when using a dose escalating regimen.
The ratio of the concentrations of two agents in a combination is referred to as the "Cratio," which may fluctuate as the combination of drugs is released, transported into the
circulatory system or CNS, metabolized, and eliminated. An objective of the present invention is to stabilize the Cratio for the combinations described herein. In some embodiments, it is preferred to reduce or even minimize the variation in the Cratio (termed "Cratio,var"). Employing the methods described herein, the release profiles of each active pharmaceutical ingredient may be modified to produce nearly constant Cratios, thereby
minimizing Cratio, var. In cases where the Tmax and Tl/2 of the NMDAr antagonist and the AChel are markedly different, e.g. by a factor of two or more, the desired release profiles will likely be dissimilar in order to minimize the relative variability of the active agents between doses.


The present invention therefore features formulations of combinations directed to
dose optimization or release modification to reduce adverse effects associated with separate
administration of each agent. The combination of the NMDAr antagonist and the AChel may
result in an additive or synergistic response, as described below.
In all foregoing aspects of the invention, at least 50%, 80, 90%, 95%, or essentially all
of the NMDAr antagonist in the pharmaceutical composition may be provided in a controlled release dosage form. In some embodiments, at least 99% of the NMDAr antagonist remains in the extended dosage form one hour following introduction of the pharmaceutical composition into a subject. The NMDAr antagonist may have a Cmax/C mean of approximately
2,1.6,1.5, 1.4,1.3,1.2 or less, approximately 2 hours to at least 8,12,16, 24 hours after the NMDAr antagonist is introduced into a subject. The AChel may also be provided in a controlled release dosage form. Thus, at least 50%, 60%, 70%, 80%, 90%, 95%, or essentially all of the AChel may be provided as a controlled release formulation. If provided as such, the AChel may have a Cmax /C mean of approximately 2, 1.6, 1.5, 1.4, 1.3, 1.2 or less,
approximately 2 hours to at least 6, 8, 12, 16, or 24 hours after the AChel is introduced into a subject.
The active pharmaceutical agents may be administered to the patient in a manner that reduces the variability of the ratio of the concentrations of the active agents over a period of time, thereby maximizing the therapeutic benefit while minimizing the side effects. The
present invention differs from prior studies by providing novel combinations as well as
formulations of combinations directed to dose optimization or release modification to reduce adverse effects associated with each agent.
Optionally, the Cratio,var of the NMDAr antagonist and the AChel is less than 100%, e.g., less than 70%, 50%, 30%, 20%, or 10% after the agents have reached steady-state
conditions. Optionally, the Cratio,var of the NMDAr antagonist and the AChel is less than 100%, e.g. less than 70%, 50%, 30%, 20%, or 10% during the first 24 hours post-administration of the agents. In some embodiments, the Cratio,var is less than about 90% (e.g., less than about 75% or 50%) of that for IR administration of the same active pharmaceutical ingredients over the first 4, 6, 8, or 12 hours after administration.
In all foregoing aspects of the invention, the NMDAr antagonist may be an
aminoadamantine derivative including memantine (l-amino-3,5-dimethyladamantane), rimantadine (1-(1 -aminoethyl)adamantane), or amantadine (1-amino-adamantane). The AChel, an acetylcholinesterase inhibitor, may be, e.g., donepezil/ARICEPT®,


rivastigmine/EXELON®, galantamine/REMINYL®, tacrine/COGNEX®, metrifonate, or huperzine-A. Thus, in some embodiments, the NMDAr antagonist is memantine while the AChel is donepezil, rivastigmine, galantamine, tacrine, metrifonate, or huperzine-A. In some embodiments, the NMDAr antagonist, the AChel, or both agents are formulated for oral, intravenous, topical, intranasal, subtopical transepithelial, subdermal, or inhalation delivery. Thus, the agents described herein may be formulated as a suspension, capsule, tablet, suppository, lotion, patch, or device (e.g., a subdermally implantable delivery device or an inhalation pump). If desired, the NMDA antagonist and the AChel may be admixed in a single composition. Alternatively, the two agents are delivered in separate
formulations sequentially, or within one hour, two hours, three hours, six hours, 12 hours, or 24 hours of each other. If administered separately, the two agents may be administered by the same or different routes of administration three times a day, twice a day, once a day, or even once every two days. Optionally, the two agents are provided together in the form of a kit. Preferably, the NMDAr antagonist and the AChel are provided in a unit dosage form.
Unless otherwise defined, all technical and scientific terms used herein have the same
meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references
mentioned herein are incorporated by reference in their entirety. In the case of conflict, the present Specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. All parts and percentages are by weight unless otherwise specified.
BRIEF DESCRIPTION OF THE FIGURES
FIGURE 1A is a graph showing that the controlled release formulation of memantine
(Namenda) and sustained release formulations of memantine (NPI-6601, NPI-6701, and NPI-6801). The sustained release formulations contain 22.5 mg of memantine. These dissolution profiles were obtained from a USP II Paddle system using water as the medium.
FIGURE IB is a graph showing predicted plasma blood levels for 24 hours of dosing
with an immediate release formulation of memantine (Namenda) and sustained release
formulations of memantine (NPI-6601, NPI-6701, and NPI-6801), obtained using the Gastro-Plus software package v.4.0.2. The sustained release formulations contain 22.5 mg of memantine.


FIGURE 1C is a graph predicting plasma blood levels at steady state for an immediate
release formulation of memantine (Namenda) and sustained release formulations of
memantine (NPI-6601, NPI-6701, and NPI-6801), obtained using the Gastro-Plus software
package v.4.0.2. The sustained release formulations contain 22.5 mg of memantine.
FIGURE 2 shows dissolution profile of A) Sustained Release (SR) Memantine (fast) -
Immediate Release (IR) Donepezil (NPI-6170), B) SR Memantine (medium) - IR Donepezil (NPI-6270) and C) SR Memantine (slow) - IR Donepezil (NPI-6370).
FIGURE 3 shows dissolution profile of A) SR Memantine (fast) - SR Donepezil (fast) (NPI-6171), B) SR Memantine (medium) - SR Donepezil (fast) (NPI-6271), C) SR Memantine (slow) - SR Donepezil (fast) (NPI-6371).
FIGURE 4 shows dissolution profile of A) SR Memantine (fast) - SR Donepezil (medium) (NPI-6172), B) SR Memantine (medium) - SR Donepezil (medium) (NPI-6272), C) SR Memantine (slow) - SR Donepezil (medium) (NPI-63 72).
FIGURE 5 shows dissolution profile of A) SR Memantine (fast) - SR Donepezil (slow) (NPI-6173), B) SR Memantine (medium) - SR Donepezil (Slow) (NPI-6273), C) SR Memantine (slow) - SR Donepezil (slow) (NPI-6373).
FIGURE 6 shows plasma concentrations obtained using the GastroPlus software package v.4.0.2 for the following compositions: A) SR Memantine (fast) — IR Donepezil (NPI-6170), B) SR Memantine (fast) - SR Donepezil (Slow) (NPI-6173), C) SR Memantine (medium) - SR Donepezil (medium) (NPI-6272), D) SR Memantine (Slow) - IR Donepezil (NPI-6370), E) SR Memantine (Slow) SR Donepezil (slow) (NPI-6373).
FIGURE 7 shows plasma concentrations obtained using the GastroPlus software
package v.4.0.2 for an SR Memantine - SR Donepezil forumulation (NPI-6272) and an IR
Memantine - IR Donepezil formulation.
FIGURE 8 shows pharmacokinetic properties of various IR formulations and SR
formulations of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides methods and compositions for treating or preventing CNS-related conditions, including psychiatric disorders (e.g., panic syndrome, general
anxiety disorder, phobic syndromes of all types, mania, manic depressive illness, hypomania, unipolar depression, depression, stress disorders, PTSD, somatoform disorders, personality disorders, psychosis, and schizophrenia), and drug dependence (e.g., alcohol,


psychostimulants (e.g., crack, cocaine, speed, and meth), opioids, and nicotine), epilepsy, headache, acute pain, chronic pain, neuropathies, cereborischemia, dementias (including Alzheimer's type), movement disorders, and multiple sclerosis. The combination includes a first agent that is an NMDAr antagonist and an AChel (e.g., donepezil/ARICEPT®, rivastigmine/EXELON®, galantamine/REMINYL®, tacrine/COGNEX®, metrifonate, or
huperzine-A). The combination is administered such that the symptoms associated with CNS-related condition are alleviated or prevented, or alternatively, such that progression of the CNS-related condition is reduced. Desirably, either of these two agents, or even both agents, is formulated for extended release, thereby providing a concentration over a desired time
period that is high enough to be therapeutically effective but low enough to reduce or avoid adverse events associated with excessive levels of either agent in the subject. Preferably, the compositions of the present invention are formulated to provide a concentration ratio variability over the dosing interval that is less than that observed or predicted for formulations where neither component or only one component is in an extended release form.

NMDAr Antagonists
Any NMDAr antagonist can be used in the methods and compositions of the invention, particularly those that are non-toxic when used in the combination of the invention. The term "nontoxic" is used in a relative sense and is intended to designate any
substance that has been approved by the United States Food and Drug Administration
("FDA") for administration to humans or, in keeping with established regulatory criteria and practice, is susceptible to approval by the FDA or similar regulatory agency for any country for administration to humans or animals.
The NMDAr antagonist may be an amino-adamantane compound including, for
example, memantine (l-amino-3,5-dimethyladamantane), rimantadine (1-(1 -
aminoethyl)adamantane), amantadine (1-amino-adamantane), as well as pharmaceutically acceptable salts thereof. Memantine is described, for example, in U.S.Patent Nos. 3,391,142; 5,891,885; 5,919,826; and 6,187,338. Amantadine is described, for example, in U.S. Patent Nos. 3,152,180; 5,891,885; 5,919,826; and 6,187,338. Additional aminoadamantane
compounds are described, for example, in U.S. Patent Nos. 4,346,112; 5,061,703; 5,334,618; 5,382,601; 6,444,702; 6,620,845; and 6,662,845. All of these patents are incorporated herein by reference.


Further NMDAr antagonists that may be employed include, for example, ketamine, eliprodil, ifenprodil, dizocilpine, remacemide, iamotrigine, riluzole, aptiganel, phencyclidine, flupirtine, celfotel, felbamate, neramexane, spermine, spermidine, levemopamil, dextromethorphan ((+)-3-hydroxy-N-methylmorphinan) and its metabolite, dextrorphan ((+)- 3-hydroxy-N-methylmorphinan), a pharmaceutically acceptable salt or ester thereof, or a metabolic precursor of any of the foregoing.
The pharmaceutical composition may be formulated to provide memantine in an amount ranging between 1 and 80 mg/day, 5 and 40 mg/day, or 10 and 20 mg/day; amantadine in an amount ranging between 25 and 500 mg/day, 25 and 300 mg/day, or 100 and 300 mg/day; or dextromethorphan in an amount ranging between 1 and 5000 mg/day, 1 and 1000 mg/day, 100 and 800 mg/day, or 200 and 500 mg/day. Pediatric doses will typically be lower than those determined for adults. Representative dosing can be found in the PDR by anyone skilled in the art.
Table 1 shows exemplary the pharmacokinetic properties (e.g., Tmax and Tl/2) of 15 memantine, amantadine, and rimantadine.
Table 1. Pharmacokinetics and Tox in humans for selected NMDAr antagonists

Compound HumanPK (t'½)in hrs Tmax in hrs Normal Dose Dose Dependent Tox
Memantine 60 3 10-20 mg/day, starting at 5mg Dose escalation required, hallucination
Amantadine 15 3 100-300 mg/day Hallucination
Rimantadine 25 6 100-200 mg/day Insomnia
Acetylcholinesterase Inhibitor
The AChel of the combination described herein is an acetylcholinesterase inhibitor (e.g., donepezil/ARICEPT®, rivastigmine/EXELON®, galantamine/REMINYL®, tacrine/COGNEX®, metrifonate, or huperzine-A).
Donepezil, described in US Patent 4,895,841, galantamine, described in US Patent 4,663,318, and rivastigmine, described in US Patent 4,948,807, are all presently approved by the United States FDA for the treatment of mild to moderate Alzheimer's disease. The use of these AChels commonly results in severe nausea, diarrhea, vomiting, and other side effects, including cardiovascular side effects, most of which are dose dependent. Furthermore, the


interruption of therapy typically requires re-titration of the dosing starting at the lowest levels (Am. Fam. Phys. 68(7): 136572 (2003)). Ultimately, patients cannot tolerate chronic AChel therapy.
The pharmaceutical composition may be formulated to provide donepezil in an
amount ranging between 1 and 10 mg/day, 2 and 5 mg/day, or 2 and 4 mg/day; rivastigmine
in an amount ranging between 1 and 12 mg/day, 2 and 6 mg/day, or 2 and 5 mg/day; or
galantamine in an amount ranging between 1 and 24 mg/day, 2 and 16 mg/day, or 2 and 12
mg/day. Pediatric doses will typically be lower than those determined for adults.
Representative dosing can be found in the PDR by anyone skilled in the art.
Table 2 shows exemplary the pharmacokinetic properties (e.g., Tmax and Tl/2) of
donepezil, rivastigmine, galantamine, and Huperzine-A.
Table 2. Pharmacokinetics and Tox in humans for selected Achels






Making Controlled Release Formulations
A pharmaceutical composition according to the invention is prepared by combining a desired NMDAr antagonist or antagonists with one or more additional ingredients that, when administered to a subject, causes the NMDAr antagonist to be released at a targeted
concentration range for a specified period of time. The NMDAr antagonist may be provided so that it is released at a dC/dT that is significantly reduced over an instant release (so called IR) dosage form, with an associated delay in the Tmax. The pharmaceutical composition may be formulated to provide a shift in Tmax by 24 hours, 16 hours, 8 hours, 4 hours, 2 hours, or at least 1 hour. The associated reduction in dC/dT may be by a factor of
approximately 0.05, 0.10,0.25,0.5 or at least 0.8. In addition, the NMDAr antagonist may be provided such that it is released at rate resulting in a Cmax/C mean of approximately 2 or less


for approximately 2 hours to at least 8 hours after the NMDAr antagonist is introduced into a subject.
In addition, the NMDAr antagonist may be provided such that it is released at a rate resulting in a Cmax/C mean of approximately 2 or less for approximately 2 hours to at least 8 hours after the NMDAr antagonist is introduced into a subject. Optionally, the sustained release formulations exhibit plasma concentration curves having initial (e.g., from 2 hours after administration to 4 hours after administration) slopes less than 75%, 50%, 40%, 30%, 20% or 10% of those for an IR formulation of the same dosage of the same NMDAr antagonist. The precise slope for a given individual will vary according to the NMDAr
antagonist being used or other factors, including whether the patient has eaten or not. For other doses, e.g., those mentioned above, the slopes vary directly in relationship to dose. The determination of initial slopes of plasma concentration is described, for example, by US Patent No. 6,913,768, hereby incorporated by reference.
Optionally, the composition described herein is formulated such the NMDAr
antagonist has an in vitro dissolution profile less than 70%) in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium..
Desirably, the compositions described herein have an in vitro dissolution profile that
is substantially identical to the dissolution profile shown for the formulations shown in
FIGURES 1A and 2-5 and, upon administration to a subject at a substantially constant daily dose, achieves a plasma concentration profile that is substantially identical to those shown in FIGURES 1B,6, and 7.
A release profile, i.e., the extent of release of the NMDAr antagonist over a desired
time, can be conveniently determined for a given time by calculating the Cmax/C mean for a desired time range. For example, the NMDAr antagonist can be provided so that it is released at Cmax/C mean of approximately 2 or less for approximately 2 hours to at least 6 hours after the NMDAr antagonist is introduced into a subject. One of ordinary skill in the art can prepare combinations with a desired release profile using the NMDAr antagonists and
formulation methods described below.
Optionally, the AChel may also be prepared as a controlled release formulation as described above for the NMDAr antagonist.


Using the formulations described herein, therapeutic levels may be achieved while minimizing debilitating side-effects that are usually associated with immediate release formulations. Furthermore, as a result of the reduction in the time to obtain peak plasma level and the potentially extended period of time at the therapeutically effective plasma level, the dosage frequency may be reduced to, for example, once or twice daily dosage, thereby improving patient compliance and adherence. For example, side effects including psychosis and cognitive deficits associated with the administration of NMDAr antagonists may be lessened in severity and frequency through the use of controlled-release methods that shift the Tmax to longer times, thereby reducing the dC/dT of the drug. Reducing the dC/dT of the
drug not only increases Tmax, but also reduces the drug concentration at Tmax and reduces the Cmax/Cmean ratio providing a more constant amount of drug to the subject being treated over a given period of time and reducing adverse events associated with dosing. With regards to the AChel, the lower dC/dT and Cmean will result in a lower incidence of cardiovascular or gastric side effects and other adverse events.
In addition to the specific combinations disclosed herein, combinations made of a first
NMDAr antagonist and the AChel may be identified by testing the ability of a test combination of a selected NMDAr antagonist and one or more AChels to lessen the symptoms of a CNS-related disorder. Preferred combinations are those in which a lower therapeutically effective amount of the NMDAr antagonist and/or the AChel is present
relative to the same amount of the NMDAr antagonist and/or the AChel required to obtain the same effect when each agent is tested separately.
The amounts and ratios of the NMDAr antagonist and the AChel are conveniently varied to maximize the therapeutic benefit and minimize the toxic or safety concerns. The NMDAr antagonist may range between 20% and 200% of its normal effective dose and the
AChel may range between 20% to 200% of its normal effective dose. The precise ratio may vary according to the condition being treated. In one example, the amount of memantine ranges between 2.5 and 80 mg per day and the amount of donepezil ranges between 1 and 20 mg/day.
When the memantine is in a controlled-release form, the preferred dosage range is
L0mg to 80mg per day; daily doses of about 22.5,27.5,32.5, 37.5,42.5,47.5, 52.5, 57.5, 62.5,67.5, 72.5, 77.5 mg are particularly preferred. When the donepezil is in a controlled-release form, the preferred dosage range lmg to l0mg per day; daily doses of about 1.0, 1.2, 1.4,1.6,1.8,2.0,2.2,2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8,4.0,4.2,4.4,4.6, 4.8, 5.0 mg per day


are particularly preferred. In a particularly preferred embodiment the memantine dose is 30 -45 mg per day, taken in combination with a donepezil dose of 2 - 4 mg/day, administered as a single dosage form, with no dose escalation over time. The combination dosage form preferably has sustained release formulations for memantine, donepezil or both, such that the dissolution profile of the two drugs in the combination tablet are "matched", especially with regards to the Tmax, dC/dT (normalized for the dose of NMDAr antagonist and AChel) in a human. For memantine and donepezil, which have similar pharmacokinetic properties, in vitro dissolution profiles will also be similar.
In a preferred embodiment of this invention, memantine and donepezil are formulated
into beads or pellets (as described herein) with substantially similar dissolution profiles. More preferably, beads or pellets of memantine are prepared with a dissolution profiles similar to that shown for memantine in Figure 4B and, separately, beads or pellets of donepezil are prepared with a dissolution profile similar to that shown for donepezil in the same figure. The preferred pellets are approximately 0.4 mg each and contain approximately 60 mg memantine
or donepezil and easily characterized by known methods. The beads may be filled into gelatin capsules by mass or number to achieve the preferred mass of memantine of 30-45 mg per capsules and donepezil of 2-4 mg per capsule. For example, a 42 mg memantine 3.6 mg donepezil combination may be prepared by combining 700 memantine beads with 60 donepezil beads in each capsule, equivalent to 280 mg memantine beads plus 24 mg
donepezil beads per capsule.
Additionally, different release profiles for each active pharmaceutical ingredient may be prepared and combined in prescribed ratios to adjust the release profile for each of the ingredients, enabling the more rapid development of formulations for development purposes or specialized formulations for individual products.
For a specified range a physician or other appropriate health professional will
typically determine the best dosage for a given patient, according to his sex, age, weight, pathological state, and other parameters. In some cases, it may be necessary to use dosage outside of the range stated in pharmaceutical packaging insert to treat a subject. Those cases will be apparent to the prescribing physician or veterinarian.
In some embodiments, the combinations of the invention achieve therapeutic levels
while minimizing debilitating side-effects that are usually associated with immediate release formulations. Furthermore, as a result of the delay in the time to obtain peak plasma level and the potentially extended period of time at the therapeutically effective plasma level, the


dosage frequency may be reduced to, for example, once or twice daily dosage, thereby improving patient compliance and adherence.
Accordingly, the combination of the invention allows the NMDAr antagonist and the AChel to be administered in a combination that improves efficacy and avoids undesirable side effects of both drugs. For example, side effects including psychosis and cognitive
deficits associated with the administration of NMDAr antagonists may be lessened in severity and frequency through the use of controlled-release methods that shift the Tmax to longer times, thereby reducing the dC/dT of the drug. Reducing the dC/dT of the drug not only increases Tmax, but also reduces the drug concentration at Tmax and reduces the
Cmax/Cmean ratio providing a more constant amount of drug to the subject being treated over a given period of time and reducing adverse events associated with dosing. Similarly, side effects associated with the use of AChels may also be reduced in severity and frequency through controlled release methods.
In certain embodiments, the combinations provide additive effects. Additivity is
achieved by combining the active agents without requiring controlled release technologies. In other embodiments, particularly when the pharmacokinetic profiles of the combined active pharmaceutical ingredients are dissimilar, controlled release formulations optimize the pharmacokinetics of the active pharmaceutical agents to reduce the variability of the Cratio over time. Reduction of Cratio variability over a defined time period enables a concerted
effect for the agents over that time, maximizing the effectiveness of the combination. The Cratio variability ("Cratio.var") is defined as the standard deviation of a series of Cratios taken over a given period of time divided by the mean of those Cratios multiplied by 100%. The Cratio for the controlled release formulation of drugs with significantly different pharmacokinetic properties is more consistent than for the IR administration of the same
drugs over any significant time period, including shortly after administration and at steady state.
Modes of Administration
The combination of the invention may be administered in either a local or systemic manner or in a depot or sustained release fashion. The two agents may be delivered in an oral, transdermal or intranasal formulation. In a preferred embodiment, the NMDAr antagonist, the AChel of the combination, or both agents may be formulated to provide controlled, extended release (as described herein). For example, a pharmaceutical


composition that provides controlled release of the NMDAr antagonist, the AChel, or both may be prepared by combining the desired agent or agents with one or more additional ingredients that, when administered to a subject, causes the respective agent or agents to be released at a targeted rate for a specified period of time. The two agents are preferably administered in a manner that provides the desired effect from the first and second agents in the combination. Optionally, the first and second agents are admixed into a single formulation before they are introduced into a subject. The combination may be conveniently sub-divided in unit doses containing appropriate quantities of the first and second agents. The unit dosage form may be, for example, a capsule or tablet itself or it can be an
appropriate number of such compositions in package form. The quantity of the active ingredients in the unit dosage forms may be varied or adjusted according to the particular need of the condition being treated.
Alternatively, the NMDAr antagonist and the AChel of the combination may not be mixed until after they are introduced into the subject. Thus, the term "combination"
encompasses embodiments where the NMDAr antagonist and the AChel are provided in separate formulations and are administered sequentially. For example, the NMDAr antagonist and the AChel may be administered to the subject separately within 2 days, 1 day, 18 hours, 12 hours, one hour, a half hour, 15 minutes, or less of each other. Each agent may be provided in multiple, single capsules or tablets that are administered separately to the
subject. Alternatively, the NMDAr antagonist and the AChel are separated from each other in a pharmaceutical composition such that they are not mixed until after the pharmaceutical composition has been introduced into the subject. The mixing may occur just prior to administration to the subject or well in advance of administering the combination to the subject.
If desired, the NMDAr antagonist and the AChel may be administered to the subject
in association with other therapeutic modalities, e.g., drug, surgical, or other interventional treatment regimens. Accordingly, the combination described herein may be administered simultaneously or within 14 days, 7 days, 5 days, 3 days, one day, 12 hours, 6 hours, 3 hours, or one hour of additional therapeutic modalities. Where the combination includes a non-drug
treatment, the non-drug treatment may be conducted at any suitable time so long as a
beneficial effect from the co-action of the combination and the other therapeutic modalities is achieved. For example, in appropriate cases, the beneficial effect is still achieved when the


non-drug treatment is temporally removed from the administration of the therapeutic agents, perhaps by days or even weeks.
The preparation of pharmaceutical or pharmacological compositions are known to those of skill in the art in light of the present disclosure. General techniques for formulation and administration are found in "Remington: The Science and Practice of Pharmacy, Twentieth Edition," Lippincott Williams & Wilkins, Philadelphia, PA. Tablets, capsules, pills, powders, granules, dragees, gels, slurries, ointments, solutions suppositories, injections, inhalants and aerosols are examples of such formulations.
In some embodiments, the first agent and second agent of the combination described
herein are provided within a single or separate pharmaceutical compositions.
"Pharmaceutically or Pharmacologically Acceptable" includes molecular entities and compositions that do not produce an adverse, allergic or other untoward reaction when administered to an animal, or a human, as appropriate. "Pharmaceutically Acceptable Carrier" includes any and all solvents, dispersion media, coatings, antibacterial and antifungal
agents, isotonic and absorption delaying agents and the like. The use of such media and agents for pharmaceutical active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active ingredient, its use in the therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions. "Pharmaceutically Acceptable Salts" include acid
addition salts and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, histidine, procaine and the like.

Formulations for Oral Administration
Combinations can be provided as pharmaceutical compositions that are optimized for particular types of delivery. For example, pharmaceutical compositions for oral delivery are formulated using pharmaceutically acceptable carriers that are well known in the art and
described further below. The carriers enable the agents in the combination to be formulated, for example, as a tablet, pill, capsule, solution, suspension, powder, liquid, or gel for oral ingestion by the subject.


The NMDAr antagonist, the AChel of the invention, or both agents may be provided in a controlled, extended release form. In one example, at least 50%, 90%, 95%, 96%, 97%, 98%, 99%, or even in excess of 99% of the NMDAr antagonist is provided in an extended release dosage form. A release profile, i.e., the extent of release of the NMDAr antagonist or the AChel over a desired time, may be conveniently determined for a given time by
calculating the Cmax /Cmean for a desired time range to achieve a given acute or chronic steady state serum concentration profile. Thus, upon the administration to a subject (e.g., a mammal such as a human), the NMDAr antagonist has a Cmax /Cmean of approximately 2.5,2, 1.5, or 1.0 approximately 1,1.5, 2 hours to at least 6, 8, 9,12,18,21, or 24 hours following such
administration. If desired, the release of the NMDAr antagonist may be monophasic or
multiphasic (e.g., biphasic). Moreover, the AChel may be formulated as an extended release composition, having a Cmax/Cmean of approximately 2.5,2,1.5, or 1.0, approximately 1,1.5,2 hours to at least 6, 8, 9,12,18,21, or 24 hours following administration to a subject. One of ordinary skill in the art can prepare combinations with a desired release profile using the
NMDAr antagonists and the AChel and formulation methods known in the art or described below.
As shown in Tables 1 and 2, the pharmacokinetic half-lives of the drugs of both classes vary from about 1.5 hours to 70 hours. Thus, suitable formulations may be conveniently selected to achieve nearly constant concentration profiles over an extended
period (preferably from 8 to 24 hours) thereby maintaining both agents in a constant ratio and concentration for optimal therapeutic benefits for both acute and chronic administration. Preferred Cratio,var values may be less than about 30%, 50%, 75%, 90% of those for IR administration of the same active pharmaceutical ingredients over the first 4,6, 8, or 12 hours after administration. Preferred Cratio,var values are less than about 100%, 70%, 50%, 30%,
20%, 10%.
Formulations that deliver this constant, measurable profile also allow one to achieve a monotonic ascent from an acute ratio to a desired chronic ratio for drugs with widely varying elimination half-lives. Compositions of this type and methods of treating patients with these compositions are embodiments of the invention. Numerous ways exist for achieving the
desired release profiles, as exemplified below.
In some embodiments, the first agent and second agent of the combination described herein are provided within a single or separate pharmaceutical compositions. "Pharmaceutically or Pharmacologically Acceptable" includes molecular entities and


compositions that do not produce an adverse, allergic or other untoward reaction when administered to an animal, or a human, as appropriate. "Pharmaceutically Acceptable Carrier" includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents and the like. The use of such media and agents for pharmaceutical active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active ingredient, its use in the therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions. "Pharmaceutically Acceptable Salts" include acid addition salts and which are formed with inorganic acids such as, for example, hydrochloric
or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, histidine, procaine and the like.
Suitable methods for preparing combinations in which the first agent, AChel, or both
agents are provided in extended release-formulations include those described in U.S.P.N. 4,606,909 (hereby incorporated by reference). This reference describes a controlled release multiple unit formulation in which a multiplicity of individually coated or microencapsulated units are made available upon disintegration of the formulation (e.g., pill or tablet) in the stomach of the animal (see, for example, column 3, line 26 through column 5, line 10 and
column 6, line 29 through column 9, line 16). Each of these individually coated or microencapsulated units contains cross-sectionally substantially homogenous cores containing particles of a sparingly soluble active substance, the cores being coated with a coating that is substantially resistant to gastric conditions but which is erodable under the conditions prevailing in the small intestine.
The combination may alternatively be formulated using the methods disclosed in
U.S.Patent No. 4,769,027, for example. Accordingly, extended release formulations involve prills of pharmaceutically acceptable material (e.g., sugar/starch, salts, and waxes) may be coated with a water permeable polymeric matrix containing an NMDAr antagonist and next overcoated with a water-permeable film containing dispersed within it a water soluble
particulate pore forming material.
One or both agents of the combination may additionally be prepared as described in U.S.P.N. 4,897,268, involving a biocompatible, biodegradable microcapsule delivery system. Thus, the NMDAr antagonist may be formulated as a composition containing a blend of free-


flowing spherical particles obtained by individually microencapsulating quantities of memantine, for example, in different copolymer excipients which biodegrade at different rates, therefore releasing memantine into the circulation at a predetermined rates. A quantity of these particles may be of such a copolymer excipient that the core active ingredient is released quickly after administration, and thereby delivers the active ingredient for an initial period. A second quantity of the particles is of such type excipient that delivery of the encapsulated ingredient begins as the first quantity's delivery begins to decline. A third quantity of ingredient may be encapsulated with a still different excipient which results in delivery beginning as the delivery of the second quantity beings to decline. The rate of
delivery may be altered, for example, by varying the lactide/glycolide ratio in a poly(D,L-lactide-co-glycolide) encapsulation. Other polymers that may be used include polyacetal polymers, polyorthoesters, polyesteramides, polycaprolactone and copolymers thereof, polycarbonates, polyhydroxybuterate and copolymers thereof, polymaleamides, copolyaxalates and polysaccharides.
In one embodiment of the invention, the NMDAr antagonist, the AChel, or both
agents may be provided in a controlled or extended release form with or without an immediate release component in order to maximize the therapeutic benefit of each, while reducing unwanted side effects associated with each. When these drugs are provided in an oral form without the benefit of controlled or extended release components, they are released
and transported into the body fluids over a period of minutes to several hours. Thus, the composition of the invention may contain an NMDAr antagonist and a sustained release component, such as a coated sustained release matrix, a sustained release matrix, or a sustained release bead matrix. In one example, memantine (e.g., 5-80 mg) is formulated without an immediate release component using a polymer matrix (e.g., Eudragit),
Hydroxypropyl methyl cellulose (HPMC) and a polymer coating (e.g., Eudragit). Such
formulations are compressed into solid tablets or granules or formed into pellets for capsules or tablets. Optionally, a coating such as Opadry® or Surelease® is used.
Separately prepared pellets, preferably release controlling pellets, combined in any manner provide the flexibility of making ratios of NMDAr antagonist to AChel containing
compositions ranging from 0.1:100 to 100:0.1, more preferably from 1:100 to 100:1, most preferably 1:10 to 10:1 by mass or by numbers of pellets (see Example 7), and at the desired release profiles for each of the active ingredients. Optionally, the NMDAr antagonist, the AChel, or both agents are prepared using the OROS® technology, described for example, in


U.S. Patent Nos. 6,919,373, 6,923,800,6,929,803, 6,939,556, and 6,930,128, all of which are hereby incorporated by reference. This technology employs osmosis to provide precise, controlled drug delivery for up to 24 hours and can be used with a range of compounds, including poorly soluble or highly soluble drugs. OROS® technology can be used to deliver high drug doses meeting high drug loading requirements. By targeting specific areas of the gastrointestinal tract, OROS® technology may provide more efficient drug absorption and enhanced bioavailability. The osmotic driving force of OROS® and protection of the drug until the time of release eliminate the variability of drug absorption and metabolism often caused by gastric pH and motility
Alternatively, the combination may be prepared as described in U.S.P.N. 5,395,626
features a multilayered controlled release pharmaceutical dosage form. The dosage form contains a plurality of coated particles wherein each has multiple layers about a core containing an NMDAr antagonist and/or the AChel whereby the drug containing core and at least one other layer of drug active is overcoated with a controlled release barrier layer
therefore providing at least two controlled releasing layers of a water soluble drug from the multilayered coated particle.
By way of example, extended release oral formulation can be prepared using additional methods known in the art. For example, a suitable extended release form of the
either active pharmaceutical ingredient or both may be a matrix tablet composition. Suitable matrix forming materials include, for example, waxes (e.g., carnauba, bees wax, paraffin wax, ceresine, shellac wax, fatty acids, and fatty alcohols), oils, hardened oils or fats (e.g., hardened rapeseed oil, castor oil, beef tallow, palm dil, and soya bean oil), and polymers (e.g., hydroxypropyl cellulose, polyvinylpyrrolidone, hydroxypropyl methyl cellulose, and
polyethylene glycol). Other suitable matrix tabletting materials are microcrystalline
cellulose, powdered cellulose, hydroxypropyl cellulose, ethyl cellulose, with other carriers, and fillers. Tablets may also contain granulates, coated powders, or pellets. Tablets may also be multi-layered. Multi-layered tablets are especially preferred when the active ingredients have markedly different pharmacokinetic profiles. Optionally, the finished tablet may be
coated or uncoated.
The coating composition typically contains an insoluble matrix polymer (approximately 15-85% by weight of the coating composition) and a water soluble material (e.g., approximately 15-85% by weight of the coating composition). Optionally an enteric


polymer (approximately 1 to 99% by weight of the coating composition) may be used or included. Suitable water soluble materials include polymers such as polyethylene glycol, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinylpyrrolidone, polyvinyl alcohol, and monomelic materials such as sugars (e.g., lactose, sucrose, fructose, mannitol 5 and the like), salts (e.g., sodium chloride, potassium chloride and the like), organic acids (e.g., fumaric acid, succinic acid, lactic acid, and tartaric acid), and mixtures thereof. Suitable enteric polymers include hydroxypropyl methyl cellulose, acetate succinate, hydroxypropyl methyl cellulose, phthalate, polyvinyl acetate phthalate, cellulose acetate phthalate, cellulose acetate trimellitate, shellac, zein, and polymethacrylates containing
carboxyl groups.
The coating composition may be plasticised according to the properties of the coating blend such as the glass transition temperature of the main agent or mixture of agents or the solvent used for applying the coating compositions. Suitable plasticisers may be added from 0 to 50% by weight of the coating composition and include, for example, diethyl phthalate,
citrate esters, polyethylene glycol, glycerol, acetylated glycerides, acetylated citrate esters, dibutylsebacate, and castor oil. If desired, the coating composition may include a filler. The amount of the filler may be 1% to approximately 99% by weight based on the total weight of the coating composition and may be an insoluble material such as silicon dioxide, titanium dioxide, talc, kaolin, alumina, starch, powdered cellulose, MCC, or polacrilin potassium.
The coating composition may be applied as a solution or latex in organic solvents or
aqueous solvents or mixtures thereof. If solutions are applied, the solvent may be present in amounts from approximate by 25-99% by weight based on the total weight of dissolved solids. Suitable solvents are water, lower alcohol, lower chlorinated hydrocarbons, ketones, or mixtures thereof. If latexes are applied, the solvent is present in amounts from
approximately 25-97% by weight based on the quantity of polymeric material in the latex. The solvent may be predominantly water.
The pharmaceutical composition described herein may also include a carrier such as a solvent, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents. The use of such media and agents for pharmaceutically active
substances is well known in the art. Pharmaceutically acceptable salts can also be used in the composition, for example, mineral salts such as hydrochlorides, hydrobromides, phosphates, or sulfates, as well as the salts of organic acids such as acetates, proprionates, malonates, or benzoates. The composition may also contain liquids, such as water, saline, glycerol, and


ethanol, as well as substances such as wetting agents, emulsifying agents, or pH buffering agents. Liposomes, such as those described in U.S.Patent No. 5,422,120, WO 95/13796, WO 91/14445, or EP 524,968 Bl, may also be used as a carrier.
Additional methods for making controlled release formulations are described in, e.g., U.S.Patent Nos. 5,422,123; 5,601,845; 5,912,013; and 6,194,000, all of which are hereby incorporated by reference.
Formulations for Other Routes of Administration
Alternatively, the compositions of the present invention may be administered
transdermally.. Preparation for delivery in a transdermal patch can be performed using
methods also known in the art, including those described generally in, e.g., U.S. Patent Nos. 5,186,938 ; 6,183,770; 4,861,800; 4,284,444 and WO 89/09051. A patch is a particularly useful embodiment in cases where the therapeutic agent has a short half-life or requires reduction in dC/dT. Patches can be made to control the release of skin-permeable active
ingredients over a 12 hour, 24 hour, 3 day, and 7 day period. In one example, a 2-fold daily excess of an NMD Ar antagonist is placed in a non-volatile fluid along with the opiate narcotic agent, non-steroidal anti-inflammatory agent, or anesthetic. Given the amount of the agents employed herein, a preferred release will be from 12 to 72 hours.
Transdermal preparations of this form will contain from 1% to 50% active
ingredients. The compositions of the invention are provided in the form of a viscous, nonvolatile liquid. Preferably, both members of the combination will have a skin penetration rate of at least 10-9 mole/cm2/hour. At least 5% of the active material will flux through the skin within a 24 hour period. The penetration through skin of specific formulations may be measures by standard methods in the art (for example, Franz et al., J. Invest. Derm. 64:194-
195 (1975)).
Pharmaceutical compositions containing the NMDAr antagonist and/or AChel of the combination may also be delivered in an aerosol spray preparation from a pressurized pack, a nebulizer or from a dry powder inhaler. Suitable propellants that can be used in a nebulizer include, for example, dichlorodifluoro-methane, trichlorofluoromethane,
dichlorotetrafluoroethane and carbon dioxide. The dosage may be determined by providing a valve to deliver a regulated amount of the compound in the case of a pressurized aerosol.
Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders.


The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as set out above. Preferably the compositions are administered by the oral, intranasal or respiratory route for local or systemic effect. Compositions in preferably sterile pharmaceutically acceptable solvents may be nebulized by use of inert gases. Nebulized solutions may be breathed directly from the nebulizing device or the nebulizing device may be attached to a face mask, tent or intermittent positive pressure breathing machine. Solution, suspension or powder compositions may be administered, preferably orally or nasally, from devices that deliver the formulation in an appropriate manner.
In some embodiments, for example, the composition may be delivered intranasally to
the cribriform plate rather than by inhalation to enable transfer of the active agents through the olfactory passages into the CNS and reducing the systemic administration. Devices used for this route of administration are included in U.S.Patent No. 6,715,485. Compositions delivered via this route may enable increased CNS dosing or reduced total body burden reducing systemic toxicity risks associated with certain drugs.
Additional formulations suitable for other modes of administration include rectal
capsules or suppositories. For suppositories, traditional binders and carriers may include, for example, polyalkylene glycols or triglycerides; such suppositories may be formed from mixtures containing the active ingredient in the range of 0.5% to 10%, preferably l%-2%. The combination may optionally be formulated for delivery in a vessel that provides
for continuous long-term delivery, e.g., for delivery up to 30 days, 60 days, 90 days, 180 days, or one year. For example the vessel can be provided in a biocompatible material such as titanium. Long-term delivery formulations are particularly useful in subjects with chronic conditions, for assuring improved patient compliance, and for enhancing the stability of the combinations.
Formulations for continuous long-term delivery are provided in, e.g., U.S.Patent Nos. 6,797,283; 6,764,697; 6,635,268, and 6,648,083.
If desired, the agents may be provided in a kit / as a combined preparation. The kit / combined preparation can additionally include instructions for use. In some embodiments, the kit / combined preparation includes in one or more containers the NMDAr antagonist and,
separately, in one or more containers, the AChel described herein. The NMDAr antagonist and AChel may be mixed together prior to administration or may be administered separately to the subject. Where they are administered separately to the patient they may be administered at the same time as separate formulations, at different times and over different


periods of time, which may be separate from one another or overlapping. The NMDAr antagonist and AChel may be administered in any order.
In other embodiments, the kit / combined preparation provides a combination with the NMDAr antagonist and the AChel mixed in one or more containers. The kits / combined 5 preparations include a therapeutically effective dose of an agent for treating dementia or other CNS-related condition.
Preparation of a pharmaceutical composition for delivery in a subdermally implantable device can be performed using methods known in the art, such as those described in, e.g., U.S. Patent Nos. 3,992,518; 5,660,848; and 5,756,115.

Indications Suitable for Treatment with the Combination
Any subject experiencing or at risk of experiencing a CNS-related disorder including dementia (e.g., Alzheimer's disease, Parkinson's disease, Picks disease, fronto-temporal dementia, vascular dementia, normal pressure hydrocephalus, HD, and MCI),
neuro-related conditions, dementia-related conditions, such as epilepsy, seizure disorders,
acute pain, chronic pain, chronic neuropathic pain may be treated using the combinations and methods described herein. Epileptic conditions include complex partial, simple partial, partials with secondary generalization, generalized—including absence, grand mal (tonic clonic), tonic, atonic, myoclonic, neonatal, and infantile spasms. Additional specific epilepsy
syndromes are juvenile myoclonic epilepsy, Lennox-Gastaut, mesial temporal lobe epilepsy, nocturnal frontal lobe epilepsy, progressive epilepsy with mental retardation, and progressive myoclonic epilepsy. The combinations of the invention are also useful for the treatment and prevention of pain caused by disorders including cerebrovascular disease, motor neuron diseases (e.g., ALS, Spinal motor atrophies, Tay-Sach's, Sandoff disease, familial spastic
paraplegia), neurodegenerative diseases (e.g., familial Alzheimer's disease, prion-related diseases, cerebellar ataxia, Friedrich's ataxia, SCA, Wilson's disease, RP, ALS, Adrenoleukodystrophy, Menke's Sx, cerebral autosomal dominant arteriopathy with subcortical infarcts (CADASIL); spinal muscular atrophy, familial ALS, muscular dystrophies, Charcot Marie Tooth diseases, neurofibromatosis, von-Hippel Lindau, Fragile
X, spastic paraplesia, psychiatric disorders (e.g., panic syndrome, general anxiety disorder, phobic syndromes of all types, mania, manic depressive illness, hypomania, unipolar depression, depression, stress disorders, PTSD, somatoform disorders, personality disorders, psychosis, and schizophrenia), and drug dependence (e.g., alcohol, psychostimulants (eg,


crack, cocaine, speed, meth), opioids, and nicotine), Tuberous sclerosis, and Wardenburg syndrome), strokes (e.g, thrombotic, embolic, thromboembolic, hemmorhagic, venoconstrictive, and venous), movement disorders (e.g., PD, dystonias, benign essential tremor, tardive dystonia, tardive dyskinesia, and Tourette's syndrome), ataxic syndromes, disorders of the sympathetic nervous system (e.g., Shy Drager, Olivopontocerebellar
degeneration, striatonigral degenration, PD, HD, Gullian Barre, causalgia, complex regional pain syndrome types I and II, diabetic neuropathy, and alcoholic neuropathy), Cranial nerve disorders (e.g., Trigeminal neuropathy, trigeminal neuralgia, Menier's syndrome, glossopharangela neuralgia, dysphagia, dysphonia, and cranial nerve palsies), myelopethies,
traumatic brain and spinal cord injury, radiation brian injury, multiple sclerosis, Post-menengitis syndrome, prion diseases, myelities, radiculitis, neuropathies (e.g., Guillian-Barre, diabetes associated with dysproteinemias, transthyretin-induced neuropathies, neuropathy associated with HIV, neuropathy associated with Lyme disease, neuropathy associated with herpes zoster, carpal tunnel syndrome, tarsal tunnel syndrome, amyloid-
induced neuropathies, leprous neuropathy, Bell's palsy, compression neuropathies,
sarcoidosis-induced neuropathy, polyneuritis cranialis, heavy metal induced neuropathy, transition metal-induced neuropathy, drug-induced neuropathy), axonic brain damage, encephalopathies, and chronic fatigue syndrome. All of the above disorders may be treated with the combinations and methods described herein.

Administration of the Compositions
Immediate release formulations of memantine (e.g., Namenda) are typically administered at low doses (e.g., 5mg/day) and progressively administered at increasing frequency and dose over time to reach a steady state serum concentration that is
therapeutically effective. According to the manufacturer's recommendation, Namenda, an immediate release formulation of memantine, is first administered to subjects at a dose of 5 mg per day. After a period of time, subjects are administered with this dose twice daily. Subjects are next administered with a 5 mg and l0mg dosing per day and finally administered with 10 mg Namenda twice daily. Using this approved dosing regimen, a
therapeutically effective steady state serum concentration may be achieved within about thirty days following the onset of therapy. Using a sustained release formulation (at a constant daily dose of 22.5 mg, for example), a therapeutically effective steady state concentration may be achieved substantially sooner, without using a dose escalating regimen.


Such concentration is predicted to be achieved within 13 days of the onset of therapy. Furthermore, the slope during each absorption period for the sustained release formulation is less (i.e. not as steep) as the slope for Namenda. Accordingly, the dC/dt of the sustained release formulation is reduced relative to the immediate release formulation even though the dose administered is larger than for the immediate release formulation. Based on this model, a sustained release formulation of memantine may be administered to a subject in an amount that is approximately the full strength dose (or that effectively reaches a therapeutically effective dose) from the onset of therapy and throughout the duration of treatment. Accordingly, a dose escalation would not be required. Similarly, the controlled release
methods described herein may be employed to reduce the dC/dT for other NMDAr antagonists or AChels enabling the administration of the combinations without the requirement for dose escalation.
Treatment of a subject with the combination may be monitored using methods known in the art. The efficacy of treatment using the combination is preferably evaluated by
examining the subject's symptoms in a quantitative way, e.g., by noting a decrease in the
frequency of adverse symptoms, behaviors, or attacks, or an increase in the time for sustained worsening of symptoms. In a successful treatment, the subject's status will have improved (i.e., frequency of relapses will have decreased, or the time to sustained progression will have increased).
The invention will be illustrated in the following non-limiting examples.
Example 1: In vivo method for determining optimal steady-state concentration ratio(Cratio,ss)

A dose ranging study is performed using, for example, the dementia model (APP23 mouse model described by Van Dam et al. (See Psychopharmacology 2005, 180(1): 177-190), or the Tg2576 model described by Dong et al (Psychopharmacology 2005, 181(1):145-152). An isobolic experiment ensues in which the drugs are combined in fractions of their EDXXs to add up to ED100 (e.g., ED50:ED50 or ED25:ED75). The plot of the data is constructed. The experiment points that lie below the straight line between the ED50 points on the graph are indicative of synergy, points on the line are indicative of additive effects, and points
above the line are indicative of inhibitory effects. The point of maximum deviation from the isobolic line is the optimal ratio. This is the optimal steady state ratio (Cratio,ss) and is adjusted based upon the agents half-life. Similar protocols may be applied in a wide variety


of validated animal models.
Example 2: Combinations of an NMDAr antagonist and an AChel
Representative combination ranges and ratios are provided below for compositions of the invention. The ranges given in Table 3 are based on the formulation strategies described herein.
Table 3: Adult Dosage and Ratios for Combination Therapy

Achel Quantity, mg/day / ACheI:NMDA Ratio Range)
NMDA drug mg/day Donepezil/ ARICEPT* Rivastigmine/ EXELON® Galantmine/ REMINYL® Tacrine/ COGNEX® Huperzine-A Metrifonate
Memantine/ 2.5-80 1-20 (0.012-8) 1-24 (0.012-9.6) 3-48 (0.038-19) 8-160 (0.1-64) 0.02-0.8 (0.0025-0.32) 8-80 (0.1-32)
Amantadine/ 50-400 1-20(0.0025-0.4) 1-24 (0.0025-0.48) 3-48(0.0075-0.96) 8-160 (0.02-3.2) 0.02-0.8(0.0005-0.016) 8-80 (0.02-1.6)
Rimantadine/ 50-200 1-20 (0.005-0.4) 1-24 (0.005-0.48) 3-48 (0.015-0.96) 8-160 (0.04-3.2) 0.02-0.8(0.0001-0.016) 8-80 (0.04-1.6)
Example 3: Release profile of memantine and galantamine
Release proportions are shown in Table 4 below for a combination of memantine and galantamine. The cumulative fraction is the amount of drug substance released from the formulation matrix to the serum or gut environment (e.g., U.S.Patent No. 4,839,177) or as measured with a USPII Paddle system using water as the dissolution medium. 15
Table 4: Release profile of memantine and donepezil

MEMANTINE Tl/2 = 60 hrs GALANTAMINE Tl/2 = 7 hrs
Time cum. fraction A cum. fraction B
l 0.2 0.2
2 0.3 0.3
4 0.4 0.4
8 0.5 0.5
12 0.6 0.6
16 0.7 0.7
20 0.8 0.8


24 0.9 1.0
Example 4: Tablet containing a combination of memantine and galantamine
An extended release dosage form for administration of memantine and galantamine is prepared as three individual compartments. Three individual compressed tablets are prepared, each having a different release profile, are encapsulated into a gelatin capsule which is then closed and sealed. The components of the three tablets are as follows.
Table 5: Immediate Release Dosage form

Component Function Amount per tablet
TABLET 1 (immediate release) :
Memantine Active agent 0 mg
Galantamine HBr Active agent 10.25 mg
Dicalcium phosphate dihydrate Diluent 26.6 mg
Microcrystalline cellulose Diluent 26.6 mg
Sodium starch glycolate Disintegrant 1.2 mg
Magnesium Stearate Lubricant 0.6 mg
Table 6: Delayed Release (3-5 hours) Dosage form

Component Function Amount per tablet
TABLET 2 (3-5 hour release):
Memantine Active agent 10 mg
Galantamine HBr Active agent 10.25 mg
Dicalcium phosphate dihydrate Diluent 26.6 mg
Microcrystalline cellulose Diluent 26.6 mg
Sodium starch glycolate Disintegrant 1.2 mg
Magnesium Stearate Lubricant 0.6 mg
Eudragit RS30D Delayed release 4.76 mg
Talc Coating component 3.3 mg
Triethyl citrate Coating component 0.95 mg
Table 7: Delayed Release (7-10 hours) Dosage form

Component Function Amount per tablet
TABLET 3 (Release delayed 7-10 hours):
Memantine Active agent 12.5 mg
Galantamine HBr Active agent 5.125 mg


Dicalcium phosphate dihydrate Diluent 26.6 mg
Microcrystalline cellulose Diluent 26.6 mg
Sodium starch glycolate Disintegrant 1.2 mg
Magnesium Stearate Lubricant 0.6 mg
Eudragit RS30D Delayed release 6.5 mg
Talc Coating component 4.4 mg
Triethyl citrate Coating component 1.27 mg
The tablets are prepared by wet granulation of the individual drug particles and other core components as may be done using a fluid-bed granulator, or are prepared by direct compression of the admixture of components. Tablet 1 (Table 5) is an immediate release dosage form, releasing the active agents within 1-2 hours following administration. It contains no memantine to avoid the dC/dT effects of the current dosage forms. Tablets 2 (Table 6) and 3 (Table 7) are coated with the delayed release coating material as may be carried out using conventional coating techniques such as spray-coating or the like. The specific components listed in the above tables may be replaced with other functionally equivalent components, e.g., diluents, binders, lubricants, fillers, coatings, and the like.
Oral administration of the capsule to a patient will result in a release profile having three pulses, with initial release of galantamine from the first tablet being substantially immediate, release of the memantine and galantamine from the second tablet occurring 3-5 hours following administration, and release of the memantine and galantamine from the third tablet occurring 7-10 hours following administration.
Example 5: Pellets containing memantine or donepezil
Memantine HC1 (or Donepezil HC1) containing pellets were prepared by wet massing. Memantine HC1 (or Donepezil HC1) was weighed and sieved through a No. 20 screen into the bowl of low shear planetary mixer. To this, microcrystalline cellulose was weighed and
added through No. 20 screen and blended with Memantine HC1 (or Donepezil HC1) using a spatula, then in a planetary mixer on low speed. Eudragit NE 400, accurately weighed was incrementally added to the powder blend, allowing sufficient time between additions for complete distribution. To avoid accumulation at the bottom and to loosen the material, the bottom was periodically scraped. Purified water was blended into the mixture in 10 mL
increments (the first of which was used to rinse the beaker containing Eudragit NE 40D) until a uniform blend appropriate for extrusion was obtained. Experimental batches were prepared
with 10 to 50 ml water. Wet massing was followed by extrusion, spheronization and drying by procedures well known in the prior art.
Table 8: Pellets containing Memantine HC1

Component Supplier Percent in Formula1 Wt. solid oer Batch (arams) Taraet Wt. Der Actual Wt. oer Batch (a)
Batch (a)

Memantine HCI 20.0% 50.0 50.0 50.00
Eudragit NE 40D Degussa 30.0% 75.0 187.5 187.50
Microcrystailine Cellulose (AvicelPH101) FMC Corp 50.0% 125.0 125.0 125.00
Purified Water N/A N/A 50.0 10.0
TOTAL 100.0% 250.0 N/A N/A
based on solid in the final product
Table 9: Pellets containing Donepezil HCI

Component Supplier Percent in Formula1 Wt. solid Der Batch (arams) Taraet Wt. Der Actual Wt. Der Batch (a)
Batch (a)

Donepezil HCI 20.0% 40.0 40.0 39.98
Eudragit NE 40D Degussa 30.0% 60.0 150.0 150.05
Vlicrocrystalline Cellulose (AvicelPH101) FMC Corp 50.0% 100.0 100.0 100.00
Purified Water N/A N/A 50.0 10.0
TOTAL 100.0% 200.0 N/A N/A
1 based on solid in the final product
Example 6: Memantine HCl/Donepezil HCI Formulations
Formulations of Sustained Release (SR) Memantine HCI (or Donepezil HCI), fast and medium, were obtained by applying a subcoat of Opadry (2% final pellet weight) followed by a functional coating of Surelease (15% dispersion prepared from 25% Surelease) to 20% Memantine HCI (or Donepezil HCI) pellets.
Formulations of Sustained Release (SR) Memantine HCI (or Donepezil HCI), slow, were obtained by applying a subcoat of Opadry (10% final bead weight), functional coating of plasticized Eudragit RS (35% final pellet weight) and triethylcitrate (plasticizer, 10% of the functional coating) to 20% Memantine HCI (or Donepezil HCI) pellets.


Table 10: Memantine SR Products

Product SR Memantine Pellets (Fast) SR Memantine Pellets (Medium) SR Memantine Pellets (Slow)
label Claim" (mg active/mg pellets) 0.164 Blend of 40%"Fast" and 60%"Slow" 0.100
Sample weight (mgpellets)16 hr "Assay" Value (mgreleased) 134.6 23.41 136.2 23.44 207.9 17.97 208.9 18.24
"Assay" Value (mg active/mg pellets) 0.174 0.172 0.0864 0.0873
Average Assay Value (mg active/mg pellets) 0.173 0.0869
Amount of pellets for 22.5 mg dose (mg) 130.0 52.0 155.4 259.0
Table 11: Donepezil Immediate Release (IR) Product

Product IR Donepezil HCI
'Label Claim" (mg active/mg granulation) 0.0357
Sample weight (mg pellets) 140.6 143.7
"Assay" Value (mg released) 4.25 4.28
"Assay" Value (mg active/mg granulation) 0.0302 0.0298
Average Assay Value (mg active/mg gran) 0.030
Amount of granulation for 5 mg dose (mg) 166.7
Table 12: Donepezil SR Product

Product SR Donepezil HCI Pellets (Fast) SR Donepezil HCI Pellets (Medium) SR Donepezil HCI Pellets (Slow)
'Label Claim" (mg active/mg pellets) 0.180 0.166 0.156
Sample weight (mgsellets) 113.8 113.9 135.6 135.5 128.8 128.3
16 hr "Assay" Value (mg released) 20.03 20.00 23.26 23.46 19.27 19.86
"Assay" Value (mg 0.176 0.176 0.172 0.173 0.150 0.155


active/mg pellets) 1 | |
Average Assay Value (mg active/mg pellets) 0.176 0.172 0.152
Amount of pellets for 5 mg dose (mg) 28.4 29.0 32.8
Example 7: Dosage formulation of Memantine-Donepezil combination
Various combinations of memantine and donepezil were prepared by filling the respective pellets in hard gelatin capsules as shown in Table 13. The separately prepared pellets provide the flexibility of making ratios of memantine to donepezil pellets ranging from 0.1:100 to 100:0.1, more preferably from 1:100 to 100:1, most preferably 1:10 to 10:1.
Table 13: Memantine-Donepezil Dosage Combinations

Product MemantineWt. solid/dosage Unit Formulation (inmg) DonepezilWt. solid/dosage Unit Formulation (inmg)
NPI-6170 130.0 SR(Fast) 166.7 IR
NPI-6270 52.0 SR (Fast) 155.4 SR(Slow) 166.7 IR
NPI-6370 259.0 SR(Slow) 166.7 IR
NPI-6171 130.0 SR(Fsst) 28.4 SR(Fast)
NPI-6271 52.0 SR (Fast) 155.4 SR(Slow) 28.4 SR(Fast)
NPI-6371 259.0 SR(Slow) 28.4 SR(Fast)
NPI-6172 130.0 SR(Fast) 29.0 SR (medium)
NPI-6272 52.0 SR(Fast) 155.4 SR(Slow) 29.0 SR (medium)
NPI-6372 259.0 SR(Slow) 29.0 SR (medium)
NPI-6173 130.0 SR(Fast) 32.8 SR (Slow)
NPI-6273 52.0 SR (Fast) 32.8 SR (Slow)


155.4 SR(Slow)
NPI-6373 259.0 SR (Slow) 32.8 SR(Slow)
SR=Sustained Release, IR=Immediate Release
Example 8: Dissolution Profiles
The dissolution profiles of the various memantine-donepezil combinations (as shown in Example 7) were obtained from USP II (paddle) dissolution system at 50 rpm, at a
temperature of 37.0 ±0.5°C, using water as the medium (Figures 2A-2C, 3A-3C, 4A-4C and 5A-5C).
For the dissolution analysis, 10 mL dissolution solutions of memantine and donepezil were diluted with 3 mL of 0.1% formic acid. Standards of memantine or donepezil were also
prepared and diluted with 3 mL of 0.1% formic acid. A 1 mL aliquot of the diluted solution or standard was transferred into an HPLC vial. A 10 mL aliquot of the solution or standard was injected onto the LC/MS/MS for analysis. A C 18 reversed phase column (Phenomenex, Luna 5|i, Phenyl-Hexyl 50 x2 mm) was used for analysis. Memantine and donepezil were separated from endogenous interfering substances and subsequently eluted from the HPLC
column by a mobile phase of 33% acetonitrile, 33% methanol and 34 % formic acid for mass quantification. A mass spectrometer set at mass-to-charge ratios (m/z) of 180.51>162.70 and 380.14>288.18 was used to detect and quantify memantine and donepezil, respectively. Data were processed and calculated by an automated data acquisition system (Analyst 1.2, Applied Biosystems, Foster City, CA).

Example 9: Release profiles of IR and SR memantine-donepezil formulations
The in vivo release profiles were obtained using the Gastro-Plus software package v.4.0.2 (Figures 6A-6E, 7). Exemplary human PK release profiles are shown in Figure 7. The release profiles and pharmacokinetic properties for a controlled release combination product
made according to Examples 5-7 as compared to IR administration of presently marketed products are shown in Figure 7 and the table in Figure 8. For the IR administration, oral dosing is per the manufacturers' recommendation (5 mg memantine q.d., incremented on a weekly basis to 5 mg BID, l0mg in the morning and 5 mg in the evening, and 10 mg memantine b.i.d.thereafter; 5mg donepezil q.d. for two weeks, increasing to 10 mg donepezil
q.d. thereafter). For the SR formulation NPI-6272, the 22.5 mg memantine and 10 mg


donepezil are provided in a controlled release oral delivery formulation releasing the active agents as shown in Figure 4B. The SR product dC/dT is considerably lower than the IR form for a similar dose for both memantine and donepezil. As measured, the dC/dT for memantine at 22.5 mg is comparable to that for a 5 mg IR dosage form. Thus, the SR formulations provide a more gradual increase in the drug during each patient dose..
In addition to achieving the desired release profile, this combination formulation will exhibit a preferred decrease Cmax/Cmean, even with a higher dose of the NMDAr antagonist and AChel, thus the present invention may provide greater doses for increased therapeutic effect without escalation that might otherwise be required. Furthermore, the increased dosing allows less frequent administration of the therapeutic agents.
Example 10: A patch providing extended release of memantine and rivastigmine
As described above, extended release formulations of an NMDAr antagonist are formulated for topical administration. Memantine transdermal patch formulations are
prepared as described, for example, in U.S.Patent Nos. 6,770,295 and 6,746,689.
For the preparation of a drug-in-adhesive acrylate, 5 g of memantine and 1 g of rivastigmine are dissolved in 10 g of ethanol and this mixture is added to 20 g of Durotak 387-2287 (National Starch & Chemical, U.S.A.). The drug gel is coated onto a backing membrane (Scotchpak 1012; 3M Corp., U.S.A.) using a coating equipment (e.g., RK Print
Coat Instra. Ltd, Type KCC 202 control coater). The wet layer thickness is 400 urn. The laminate is dried for 20 minutes at room temperature and then for 30 minutes at 40°C. A polyester release liner is laminated onto the dried drug gel. The sheet is cut into patches and stored at 2-8 °C until use (packed in pouches). The concentration of memantine in the patches ranges between 5.6 and 8 mg/cm2, while rivastigmine ranges between 1.1 and 1.6 mg/cm2.
The nearly continuous infusion of the components provides a much more consistent Cratio over time maximizing the additive or synergistic effects of the combinations of the present invention to achieve the optimal therapeutic effects.
Example 11: Multiple dose safety study in Alzheimer's patients with an extended release memantine, extended release donepezil combination.
A study to determine safety and pharmacokinetics of an extended release combination formulation of memantine and donepezil is described below. The study results are expected


to assess the frequency of adverse events as well as evaluate the pharmacokinetic parameters at higher doses.

Purpose To determine the safety and pharmacokinetics of repeated doses of drug.
Dosage: Based on previous single ascending dose (SAD) study, either e.g. 22.5 mg memantine SR + 4 mg donepezil SR, 45 mg memantine SR + 4 mg donepezil SR, or 45 mg memantine SR + 8 mg donepezil SR, QD for 30 days
Concurrent Controls memantine IR or memantine IR plus donepezil IR (both dosed as per manufacturers' labels)
Route: Oral
Subject Population: Males or females diagnosed with dementia of the Alzheimer's type. (Age range 50-80?)
Structure: 4 arm
Study Sites: TBD
Blinding: Patients blinded
Method of Subject Assignment: Random with equal number of males and females in each group and equal age distributions within groups
Total Sample Size: 24 Subjects 6 per dosing arm
Primary Efficacy Endpoint: None
Adverse Events: Monitored at least twice daily for behavioral, cardiovascular, and gastrointestinal effects reported for high doses of memantine or donepezil (including dizziness, headache, confusion, constipation, hypertension, coughing, nausea, diarrhea, vomiting).
Blood Collection By canula through first day of study period then 2-4 times daily for rest of study
Analysis Assays to measure memantine, donepezil, and potentially other physiological parameters, adverse


events

Example 12: Treatment of Alzheimer's patients with an extended release memantine, extended release donepezil combination .
A study to determine effectiveness of two extended release combination formulations of memantine and donepezil is described below. The study results are expected to establish a more rapid onset of efficacy without increase in adverse effects (confirming tolerability of a non-dose escalating dosing regimen (i.e., administration of substantially identical doses of memantine and donepezil throughout the term of dosing)).

Purpose To determine the efficacy of combination therapy, non-dose escalated
Study Dosages: 22.5 mg memantine SR +4 mg donepezil SR, 45 mg memantine SR + 4 mg donepezil SR
Concurrent Controls memantine IR (Namenda) or memantine IR plus donepezil IR (Aricept) both per manufacturers' dosing labels (as of 2004).
Route: Oral
Subject Population: Males or females diagnosed with dementia of the Alzheimer's type. (Age range 50-80)
Structure: 4arm
Study Sites: Multi-center
Blinding: Patients blinded
Method of Subject Assignment: Random with equal number of males and females in each group and equal age distributions within groups
Total Sample Size: 400 subjects, 100 per arm
Primary Efficacy Endpoint: Improvement of ADAS-Cog, SIBIC, HAM-D in or neuropsychiatric index at 7,14,21,42, 63, 84 days.
Efficacy Monitoring: Monitored twice per week for first 4 weeks, then weekly thereafter.
Adverse Events: Monitored at least twice daily for behavioral, cardiovascular and gastrointestinal effects reported


for high doses of memantine or donepezil (including dizziness, headache, confusion, constipation, hypertension, coughing, nausea, diarrhea, vomiting).
Blood Collection: By canula at the following time points:Day 1:0,4, 8,12 hoursDays 2,4, 6, 8,10, 12, 14,17, 21, 28, 35, 42,49, 56, 63, 70, 77, 84 pre-dose trough
Analysis: Efficacy, adverse events, and laboratory assays measuring study drugs.


Additional embodiments are within the claims.
What is claimed is:


1. A pharmaceutical composition comprising:
(a) an NMDAr antagonist;
(b) an acetylcholinesterase inhibitor (AChel),
wherein at least one of said NMDAr antagonist or said second agent is provided in an extended release dosage form and wherein the agent in said extended release dosage form has an in vitro dissolution profile less than 70%) in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
2. The pharmaceutical composition of claim 1, wherein said NMDAr antagonist has a dC/dT less than about 80% of the rate for the IR formulation.
3. The pharmaceutical composition of claim 1, wherein said NMDAr antagonist has a Cmax/Cmean of approximately 1.6 or less approximately 2 hours to at least 12 hours after said composition is introduced into a subject.
4. The pharmaceutical composition of claim 1, wherein the relative Cratio.var of said NMDAr antagonist and said second agent is less than 100% from 2 hour to 12 hours after said composition is introduced into a subject.
5. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is a non-dose escalating, twice per day, once per day, or once everyother day dosage form.
6. The pharmaceutical composition of claim 1, wherein the NMDAr antagonist is selected from the group consisting of memantine, amantadine, rimantadine, ketamine, eliprodil, ifenprodil, dizocilpine, remacemide, iamotrigine, riluzole, aptiganel, phencyclidine, flupirtine, celfotel, felbamate, neramexane, spermine, spermidine, levemopamil, dextromethorphan, dextrorphan, and pharmaceutically acceptable salts thereof.


7. The pharmaceutical composition of claim 1, wherein said Achel is selected from the
group consisting of donepezil, rivastigmine, tacrine, metrifonate, Huperzine-A, and
pharmaceutical^ acceptable salts thereof.
8. The pharmaceutical composition of claim 1, wherein said pharmaceutical composition is formulated for oral, transnasal, parenteral, subtopical transepithelial, transdermal patch, subdermal, or inhalation delivery.
9. The pharmaceutical composition of claim 1, wherein said pharmaceutical composition is formulated as a suspension, capsule, tablet, suppository, lotion, or patch.
10. The pharmaceutical composition of claim 1, wherein the NMDAr antagonist is memantine and the AChel is donepezil or pharmaceutically acceptable salts thereof.
11. The pharmaceutical composition of claim 6, wherein the NMDAr antagonist is memantine and wherein the composition is formulated to provide memantine in an amount of 2.5-80 mg per day, 20-67.5 mg per day, 22.5-57.5 mg per day or 42.5-80 mg per day.
12. A method of preventing or treating a CNS-related condition comprising
administering to a subject in need thereof a therapeutically effective amount of:
(a) an NMDAr antagonist; and
(b) an acetylcholinesterase inhibitor,
wherein at least one of said NMDAr antagonist or said second agent is provided in an extended release dosage form and wherein the agent in said extended release dosage form has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40%> in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
13. The method of claim 12, wherein said CNS-related condition is Alzheimer's disease
or Parkinson's disease.


14. The method of claim 12, wherein said NMDAr antagonist is provided in an extended release dosage form.
15. The method of claim 14, wherein said NMDAr antagonist is administered at a substantially identical daily dose.
16. The method of claim 15, wherein said NMDAr antagonist reaches a therapeutically effective steady state plasma concentration in said subject within fifteen days of said administering.
17. The method of claim 14, wherein said NMDAr antagonist has a dC/dT less than about 80% of the rate for the IR formulation.
18. The method of claim 14, wherein said NMDAr antagonist has a Cmax/Cmean of approximately 1.6 or less approximately 2 hours to at least 12 hours after said composition is introduced into a subject.
19. The method of claim 12, wherein the relative Cratio.var of said NMDAr antagonist and said AChel is less than 100% from 2 hour to 12 hours after said composition is introduced into a subject.
20. The method of claim 19, wherein the relative Cratio.var of said NMDAr antagonist and said AChel is less than 70% of the corresponding IR formulation from 2 hour to 12 hours after said composition is introduced into a subject.
21. The method of claim 12, wherein said NMDAr antagonist is selected from the group consisting of memantine, amantadine, rimantadine, ketamine, eliprodil, ifenprodil, dizocilpine, remacemide, iamotrigine, riluzole, aptiganel, phencyclidine, flupirtine, celfotel, felbamate, neramexane, spermine, spermidine, levemopamil, dextromethorphan, dextrorphan, and pharmaceutically acceptable salts thereof.


22. The method of claim 21, wherein said NMDAr antagonist is memantine or a pharmaceutically acceptable salt thereof.
23. The method of claim 22, wherein the amount of memantine ranges between 10 and 80 mg per dose.
24. The method of claim 23, wherein the amount of memantine ranges between 20-60 mg per dose.
25. The method of claim 23, wherein the amount of memantine ranges between 40 and 80 mg per dose.
26. The method of claim 13, wherein said acetylcholinesterase inhibitor is selected from the group consisting of donepezil, rivastigmine, tacrine, metrifonate, Huperzine-A, and pharmaceutically acceptable salts thereof.
27. The method of claim 12, wherein the NMDAr antagonist is memantine and acetylcholinesterase inhibitor is donepezil or pharmaceutically acceptable salts thereof.
28. The method of claim 12, wherein said NMDAr antagonist and said second agent are administered simultaneously or sequentially.
29. The method of claim 12, wherein said NMDA antagonist and said second agent are administered as a single composition.
30. A method of treating, preventing or reducing a condition associated with a deregulation in NMDAr activity comprising administering to a subject at risk of suffering or suffering from said condition a composition comprising an NMDAr antagonist provided in an extended release dosage form and a second agent, wherein said second agent AChel selected from the group consisting of donepezil, rivastigmine, tacrine, metrifonate, Huperzine-A; wherein said composition is administered at a substantially identical daily dose.


31. The method of claim 30, wherein said pharmaceutical composition is administered to said subject no more than once every 24 hours.
32. The method of claim 30, wherein said daily dose of said NMDAr antagonist ranges between 15 and 35 mg.
33. The method of claim 32, wherein said daily dose of said NMDAr antagonist ranges between 20 and 25 mg.
34. The method of claim 30, wherein said NMDAr antagonist reaches a therapeutically effective steady state plasma concentration in said subject within fifteen days of said administering.
35. The method of claim 30, wherein the mean plasma concentration profile of said NMDAr antagonist in said subject has an initial slope in a subject has an initial slope from 2 hours to 4 hours after administration less than 50% of that for an IR formulation of the same NMDAr antagonist at the same administered dose.

36. Use of an NMDAr antagonist and an acetylcholinesterase inhibitor in the manufacture of a combined preparation for preventing or treating a CNS-related condition wherein at least one of said NMDAr antagonist or said acetylcholinesterase inhibitor has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
37. The use according to claim 36 wherein the combined preparation comprises the NMDAr antagonist and the acetylcholinesterase inhibitor are as separate formulations.
38. The use according to claim 36 wherein the combined preparation comprises the NMDAr antagonist and the acetylcholinesterase inhibitor as a single formulation.


39. The use according to claim 38 wherein the single formulation is a non-dose escalating formulation.
40. Use of an NMDAr antagonist in the manufacture of a medicament for preventing or treating a CNS-related condition in a subject in need thereof by combination therapy wherein said combination therapy comprises administration of said NMDAr antagonist and an acetylcholinesterase inhibitor to the subject, and wherein at least one of said NMDAr antagonist or said AChel has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
41. Use of an AChel in the manufacture of a medicament for preventing or treating a CNS-related condition in a subject in need thereof by combination therapy wherein said combination therapy comprises administration of said AChel and an NMDAr antagonist to the subject, and wherein at least one of said NMDAr antagonist or said AChel has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.
42. A kit comprising:
(a) an NMDAr antagonist;
(b) an acetylcholinesterase inhibitor selected from the group consisting of donepezil, rivastigmine, tacrine, metrifonate, Huperzine-A; and
(c) instructions for treating or preventing CNS related conditions such as Alzheimer's disease,
and wherein at least one of said NMDAr antagonist or said AChel has an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium.


43. The kit of claim 42, wherein said NMDAr antagonist and said second agent are
formulated as a single formulation.
44. The pharmaceutical composition of claim 1, wherein the NMDAr antagonist and the AChel are formulated as pellets, and wherein the ratio of the active pharmaceutical ingredients and the quantities of active pharmaceutical ingredients may be varied by adjusting the quantities and ratios of pellets in the final dosage form.
45. The pharmaceutical composition of claim 44, wherein the ratio of NMDAr antagonist to AChel ranges from 0.1:100 to 100:0.1.
46. The pharmaceutical composition of claim 45, wherein the ratio of NMDAr antagonist to AChel ranges from 1:100 to 100:1.
47. A pharmaceutical composition comprising:

(a) memantine in a dose ranging between 20 and 30 mg; and
(b) donepezil in a dose ranging between 2 and 5 mg;
wherein memantine and donezepil are both provided in an extended release dosage form, said extended release dosage form having an in vitro dissolution profile less than 70% in one hour, less than 90% in two hours, greater than 40% in six hours, and greater than 85% in 12 hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° with water as a dissolution medium;
48. The pharmaceutical composition of claim 47, wherein the ratio of dosing of said composition reduces gastro-intestinal and cardiovascular side effects.
49. The pharmaceutical composition of claim 47, the release profile of memantine is substantially identical to the release profile of donepezil.


METHODS AND COMPOSITIONS FOR TREATMENT OF CNS-RELATED
CONDITIONS
Abstract of the Disclosure
The present invention provides novel methods and compositions for the treatment and prevention of CNS-related conditions. One of the CNS-related conditions treated by the methods and compositions of the invention is Alzheimer's disease.

TRA 2139976v. 1


Documents:

1779-MUMNP-2007-ABSTRACT(15-2-2011).pdf

1779-MUMNP-2007-ABSTRACT(18-7-2011).pdf

1779-MUMNP-2007-ABSTRACT(25-10-2007).pdf

1779-MUMNP-2007-ABSTRACT(GRANTED)-(18-10-2011).pdf

1779-mumnp-2007-abstract.doc

1779-mumnp-2007-abstract.pdf

1779-MUMNP-2007-AFFIDAVIT(15-2-2011).pdf

1779-MUMNP-2007-CANCELLED PAGES(8-11-2011).pdf

1779-MUMNP-2007-CLAIMS(AMENDED)-(15-2-2011).pdf

1779-MUMNP-2007-CLAIMS(AMENDED)-(18-7-2011).pdf

1779-MUMNP-2007-CLAIMS(GRANTED)-(18-10-2011).pdf

1779-MUMNP-2007-CLAIMS(MARKED COPY)-(15-2-2011).pdf

1779-mumnp-2007-claims.doc

1779-mumnp-2007-claims.pdf

1779-MUMNP-2007-CORRESPONDENCE(11-1-2010).pdf

1779-MUMNP-2007-CORRESPONDENCE(14-2-2011).pdf

1779-MUMNP-2007-CORRESPONDENCE(17-05-2010).pdf

1779-MUMNP-2007-CORRESPONDENCE(25-10-2007).pdf

1779-MUMNP-2007-CORRESPONDENCE(26-8-2009).pdf

1779-MUMNP-2007-CORRESPONDENCE(8-11-2011).pdf

1779-MUMNP-2007-CORRESPONDENCE(IPO)-(19-10-2011).pdf

1779-mumnp-2007-correspondence-others.pdf

1779-mumnp-2007-correspondence-received.pdf

1779-mumnp-2007-description (complete).pdf

1779-MUMNP-2007-DESCRIPTION(GRANTED)-(18-10-2011).pdf

1779-MUMNP-2007-DRAWING(15-2-2011).pdf

1779-MUMNP-2007-DRAWING(GRANTED)-(18-10-2011).pdf

1779-mumnp-2007-drawings.pdf

1779-MUMNP-2007-DRWING(25-10-2007).pdf

1779-MUMNP-2007-FORM 1(15-2-2011).pdf

1779-MUMNP-2007-FORM 1(8-11-2011).pdf

1779-mumnp-2007-form 13(17-05-2010).pdf

1779-MUMNP-2007-FORM 2(TITLE PAGE)-(15-2-2011).pdf

1779-MUMNP-2007-FORM 2(TITLE PAGE)-(COMPLETE)-(25-10-2007).pdf

1779-MUMNP-2007-FORM 2(TITLE PAGE)-(GRANTED)-(18-10-2011).pdf

1779-MUMNP-2007-FORM 26(27-8-2009).pdf

1779-MUMNP-2007-FORM 3(11-1-2010).pdf

1779-mumnp-2007-form 3(14-2-2011).pdf

1779-MUMNP-2007-FORM 3(15-2-2011).pdf

1779-MUMNP-2007-FORM 3(18-7-2011).pdf

1779-MUMNP-2007-FORM 3(25-10-2007).pdf

1779-MUMNP-2007-FORM 5(15-2-2011).pdf

1779-mumnp-2007-form-1.pdf

1779-mumnp-2007-form-18.pdf

1779-mumnp-2007-form-2.pdf

1779-mumnp-2007-form-26.pdf

1779-mumnp-2007-form-3.pdf

1779-mumnp-2007-form-5.pdf

1779-MUMNP-2007-GENERAL POWER OF ATTORNEY(15-2-2011).pdf

1779-MUMNP-2007-GENERAL POWER OF ATTORNEY(17-05-2010).pdf

1779-MUMNP-2007-MARKED COPY(15-2-2011).pdf

1779-MUMNP-2007-MARKED COPY(18-7-2011).pdf

1779-MUMNP-2007-OTHER DOCUMENT(15-2-2011).pdf

1779-mumnp-2007-other document(24-7-2007).pdf

1779-mumnp-2007-pct-search report.pdf

1779-MUMNP-2007-PETITION UNDER RULE 137(14-2-2011).pdf

1779-MUMNP-2007-POWER OF ATTORNEY(26-8-2009).pdf

1779-MUMNP-2007-REPLY TO EXAMINATION REPORT(15-2-2011).pdf

1779-MUMNP-2007-REPLY TO HEARING(18-7-2011).pdf

1779-mumnp-2007-wo international publication report(25-10-2007).pdf

abstract1.jpg


Patent Number 249380
Indian Patent Application Number 1779/MUMNP/2007
PG Journal Number 42/2011
Publication Date 21-Oct-2011
Grant Date 18-Oct-2011
Date of Filing 25-Oct-2007
Name of Patentee ADAMAS PHARMACEUTICALS, INC.
Applicant Address 1900 POWELL STREET, SUITE 1050 EMERYVILLE, CALIFORNIA 94608
Inventors:
# Inventor's Name Inventor's Address
1 WENT GREGORY T. 257 BUENA VISTA, MILL VALLEY, CALIFORNIA 94941
2 FULTZ TIMOTHY J. 432 VERBENA COURT, PLEASANT HILL, CALIFORNIA 94523
PCT International Classification Number A61K31/13,A61K31/137
PCT International Application Number PCT/US2006/013506
PCT International Filing date 2006-04-06
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/285,905 2005-11-22 U.S.A.
2 60/669,290 2005-04-06 U.S.A.