|Title of Invention
MODIFIED DOSAGE FORMS OF TACROLIMUS
|The present invention provides a modified release dosage form of tacrolimus that releases two or more amount of tacrolumus upon oral administration, the first amount of tacrolimus that releases two or more amount of tacrolimus upon oral administration, the first amount of tacrolimus releases from the immediate release dosage unit substantially immediately within 0-2 hours followed by a time interval ranging from about 1-10 hours during which substantially no amount of tacrolimus is released from the dosage form, after which a second amount of tacrolimus is released wherein said second amount is released from the delayed release dosage unit either immediately e.g. within 0-2 hours or over a period of time ranging from about 2-12 hours from its initial release from the delayed release dosage unit. The dosage form may further comprise additional amount of tacromlimus to provide additional pulse of tacrolimus. The dosage form of tacrolimus existing composition of tacrolimus. A method of preparing the dosage forms is also described.
THE PATENTS ACT, 1970
(39 of 1970)
THE PATENTS RULES, 2003
(See section 10 and rule 13)
MODIFIED DOSAGE FORMS OF TACROLIMUS
PANACEA BIOTEC LIMITED
A company incorporated under the laws of India having their office at 201, SAMARPAN COMPLEX, NEW-LINK ROAD, CHAKALA, ANDHERI (E), MUMBAI 400099,
The following specification describes the invention
FIELD OF THE INVENTION
The present invention relates to modified dosage forms of tacrolimus and/or its salts thereof, which exhibit improved inter-individual variability.
BACKGROUND OF THE INVENTION
Tacrolimus, known as FK-506 is a macrolide immunosuppressant produced by Streptomyces tsukubaensis). Tacrolimus is available as capsule, injection and an ointment. The capsule dosage form commercially sold as Prograf®, is approved for prophylaxis of organ rejection in patients receiving allogeneic liver, kidney or heart transplants. Absorption of orally administered tacrolimus from the gastrointestinal tract is incomplete and variable. The absolute bioavailability of tacrolimus is 17±10% in adult kidney transplant patients (N=26), 22±6% in adult liver transplant patients (N=17), 23±9% in adult heart transplantation patients (N=l 1) and 18±5% in healthy volunteers (N=16). It has been observed that the absorption is affected by the presence of food. The rate and extent of tacrolimus absorption is greatest under fasted conditions. The presence and composition of food decreases both the rate and extent of tacrolimus absorption.
Tacrolimus pharmacokinetic characteristics vary greatly among individuals. It is subject to substantial intestinal and hepatic first-pass effects. Tacrolimus is a substrate of cytochrome p450 (CYP3A), it has poor bioavailability because of this extensive metabolism and its bioavailability is individually variable. Thus, tacrolimus elimination, expressed as total body clearance, varies interindividually from 0.041 to 0.36 L . h-1 (kg of body weight)" . Because of this variability in conjunction with its narrow therapeutic index, monitoring of whole-blood concentrations of tacrolimus is essential to achieve optimal efficacy while minimizing the risk of toxicity.
Prior arts disclose that tacrolimus has been focus of intense research in the area of development of novel dosage forms exhibiting sustained release characteristics.
United States Patent 6,440,458, United States Patent 6,576,259 and United States Patent 6,884,433 relate to sustained release formulation comprising a macrolide, tacrolimus, wherein the time required for 63.2% (T63.2%) of the maximum amount of tacrolimus or its hydrate to be dissolved is 0.7 to 15 hours, as measured according to Japanese Pharmacopoeia 13th edition Dissolution Test no. 2 (Paddle method, 50 rpm) in a test solution which is aqueous 0.005% hydroxypropyl cellulose, adjusted to pH 4.5.
United States application publication 2006/0287352 relates to a modified release composition comprising tacrolimus which releases less than 20% w/w of the active ingredient within 0.5 hrs when subjected to an in-vitro dissolution test using USP paddle method and using 0.1N HC1 as dissolution medium and has increased bioavailability by effectively reducing or even avoiding the effect of CYP3A4 metabolism. The modified release composition may be enteric-coated and/or may comprise solid dispersion or solid solution of tacrolimus in a hydrophilic or water-soluble vehicle and one or more modifying
release agents; and/or may comprise of solid dispersion or solid solution of tacrolimus in an amphiphilic or hydrophobic vehicle and optionally one or more modifying release agents. The modified release dosage form of tacrolimus of '352 application mentioned above delays the release of tacrolimus to the distal part of duodenum thus reducing drug related gastro-intestinal side-effects and the relatively high degree of metabolism in the proximal part of the gastrointestinal tract (CYP3A4 mediated metabolism), however their therapeutic utility is limited by the failure to provide any rapid onset and hence faster action.
United States Patent 6,569,463 formulate a pharmaceutical composition in the form of solid carrier comprising substrate and encapsulation coat wherein the encapsulation coat comprises an admixture of a therapeutically effective amount of hydrophobic pharmaceutical active ingredient, an effective solubilizing amount of at least one hydrophilic surfactant and lipophilic additive selected from the group consisting of lipophilic surfactants, triglycerides, and combinations thereof, wherein the effective solubilizing amount of the at least one hydrophilic surfactant is an amount effective to partially or fully solubilize the pharmaceutical active ingredient in the encapsulation coat. As per the inventors, solid carrier for pharmaceutical active ingredients offer potential advantages over micronized drugs, emulsion or solubilized formulation of prior arts to enhance in-vivo performance of hydrophobic drugs
United States Patent 6,228,398 relates to modified release compositions which are essentially multiparticulate in nature. The patent chiefly discloses compositions for methylphenidate which are purported to mimic the profile of multiple immediate release doses in vivo by exhibiting well defined peaks and troughs in the plasma profile. The plasma profile achieved by the multiparticulate modified release composition is advantageous in reducing patient tolerance to methylphenidate and in increasing patient compliance by reducing dosage frequency.
As mentioned earlier, the various concerns with tacrolimus therapy are its extensive metabolism, incomplete and variable absorption, low bioavailability, food effect and side-effects. Also monitoring and maintaining tacrolimus whole blood concentrations in patients after its oral administration is essential to avoid rejection, toxicity and to improve compliance as increasing tacrolimus trough blood concentrations increases incidence of adverse events.
All these above mentioned issues are not addresses or tackled effectively in any of the prior known compositions of tacrolimus. There is definitely a need to provide a more effective and compliant therapy for this most widely prescribed immunosuppressant in organ transplantation.
The inventors of the present invention have developed modified dosage form of tacrolimus, which addresses and avoids most of the issues with tacrolimus therapy, by providing a composition which releases tacrolimus in such a manner that it eliminates the release of tacrolimus when the composition passes through the metabolizing region of cytochrome p450 system (CYP3A). The modified dosage form of tacrolimus comprises an immediate release component and at least one modified release component, which releases the drug in
such a manner that it would avoid metabolism and provide reduced inter-individual variation.
DESCRIPTION OF THE INVENTION:
The present invention provides a novel and improved modified release dosage forms of tacrolimus and/or its salt thereof comprising of an immediate release component and at least one modified release component, such that the dosage form provides a pulsatile release of tacrolimus and/or its salt thereof. As used herein, term "pulsatile release" means any pulsatile release system that releases the drug in "pulses," wherein a single dosage form provides an initial amount of tacrolimus substantially immediately upon administration to a mammal followed by a predetermined time interval of "substantially no release" after which a second amount of tacrolimus is released either immediately or over a period of time, to achieve a once-a-day therapy of tacrolimus with reduced metabolism and variability. In certain embodiments, the modified release dosage form may further comprise two or more modified release components, delivering further amounts of tacrolimus to achieve once-a-day therapy of tacrolimus. The immediate release component and modified release component(s), herein described as "dosage units", encompasses beads, granules, pellets, particles or mini-tablets filled into capsules or compressed tablets, each component releasing amounts of tacrolimus as pulses, at different time interval(s) encompassing a predetermined time internal of "substantially no release", each amount being same or different and providing the total recommended daily dose.
In a preferable embodiment pulsatile release of tacrolimus is achieved with dosage form that is a capsule comprising at least two drug-containing "dosage units" wherein each dosage unit within the capsule provides a different drug release profile i.e. immediate release and delayed release. Control of the delayed release dosage unit(s) is accomplished by a polymer coating on the dosage unit(s). Each dosage unit may comprise of plurality of drug-containing beads, granules, pellets or particles filled into capsules. Drug-containing beads can be produced by applying drug to an inert support, e.g., inert sugar beads coated with drug or by creating a "core" comprising both drug and one or more excipients or polymer as known in the art. Drug-containing "granules" and "particles" comprise drug particles that may or may not include one or more additional excipients or polymers. In contrast to drug-containing beads, the drug-containing granules and particles do not contain an inert support. Granules generally comprise drug particles and require further processing and particles which are smaller than granule are generally not further processed. Although beads, granules and particles may be formulated to provide immediate release, beads and granules are generally employed to provide delayed release.
In another embodiment of a capsule dosage form, each dosage unit may comprise of compressed or molded tablets, wherein each tablet within the capsule may provide a different drug release profile.
In another embodiment, the dosage form is a tablet comprising of "dosage units", each providing a different drug release, i.e immediate release and delayed release, wherein the
dosage units are either compacted into a single tablet or they represent integral but discrete segments thereof e.g. a multi-layered tablet. For example, drug-containing particles, granules or beads can be compressed together into a single tablet or multi-layered tablet using conventional tabletting means known in the art. In a further embodiment, the dosage form is a coated tablet or an inlay tablet that comprises an inner drug-containing core and at least one drug-containing layer surrounding the inner core, wherein the outer drug-containing layer contains the immediate release amount and the inner drug-containing core comprising of matrix polymer or a polymeric-coating contains the delayed release amounts, for two or more delayed release amounts, layers interposed between the inner core and outer layer contains the various delayed release amounts released after a predetermined time interval of substantially no drug release.
In an alternative embodiment, the dosage form of the invention may be in the form of a liquid composition, wherein the first amount of tacrolimus and/or its pharmaceutically acceptable salt, is dissolved and/or dispersed, either alone or in combination with excipient, in a pharmaceutically acceptable vehicle, to form the immediate release pulse; and the second amount of tacrolimus or its pharmaceutically acceptable salt, is also dispersed in the vehicle in the form of granules, particles, beads or pellets, to form the delayed pulse.
In preferred embodiment such modified release dosage forms of tacrolimus are designed to provide a pulsatile release in-vitro such that the dosage form when tested in a USP Type II apparatus at 75 rpm using a pH change method (first 2 hours in pH 1.2 followed by a dissolution in a pH of 4.5 for 1 hr, pH 6.8 for 1 hr and further dissolution in pH 7.4) exhibits a dissolution profile substantially corresponding to the following pattern: more than 20% of the total drug is released in 2 hours; after 4 hours, more than 20 but less than 80% of the total drug is released; and after 8 hours, not less than 60% of the total drug is released.
In such preferred embodiments the modified release dosage form is such that, a first group of beads, granules, particles or tablet releases initial amount of tacrolimus substantially immediately within 0.1 to 2 hrs following oral ingestion of the dosage form, while a second group of beads, granules, particles or tablet releases drug approximately 2 hours to 10 hours following the release of the initial amount, preferably after 3 hours to 9 hours and more preferably after 4 hours to 8 hours of first pulse. The above-mentioned beads, granules, particles and tablets of different drug release profiles (e.g., immediate and delayed release profiles) may be mixed and included in a capsule to provide a pulsatile dosage form having the desired release profile.
As will be appreciated by those skilled in the art and as described in the pertinent texts and literature, a number of methods are available for preparing drug-containing tablets, beads, granules or particles that provide a variety of drug release profiles. Such methods include, but are not limited to, the following: placing the drug within a suitable matrix, mixing the drug with suitable polymers, excipients and solvents and evaporating the solvent to form precipitates or dispersions, coating a drug or drug-containing composition with an appropriate coating material, typically although not necessarily incorporating a polymeric material; mixing or coating a drug or drug-containing composition with an appropriate
hydrophilic and/or lipophilic surfactant or additives, granulating the drug with pharmaceutical^ acceptable carrier or polymer followed by extrusion and spheronization, and forming complexes of the drug with a suitable complexing agent.
The immediate release dosage unit of the preferred dosage form comprises the drug along with conventional pharmaceutical excipients in the form of beads (beads here refer to nonpareil seeds, eg. sugar, starch, lactose or such other beads with drug as matrix or drug coated on the beads). A preferred method for forming the immediate release drug-containing beads comprises the steps of (a) dissolving drug particles along with hydrophilic and/or lipophilic surfactants or additives in suitable vehicle; (b) coating the non-pareil seeds with the solution prepared in step (a); optionally (c) coating the beads with film forming agents.
In another embodiment, immediate release dosage unit is prepared by mixing the drug and a suitable polymer in a suitable solvent optionally along with other excipients and evaporate the solvent to obtain a dried mixture which may be further subjected to size reduction to prepare solid dispersions. Solid dispersions or fine particles of drug may also be prepared by any other techniques well known in the art.
In another embodiment the immediate release dosage units is tablets (e.g., as incorporated into a capsule) and is prepared by compressing a drug-containing blend, e.g., blend of granules, prepared using a direct blend, wet-granulation or dry-granulation process as known in the art in a tablet compression machine.
The delayed release dosage units in the present composition can be prepared by further coating a drug or drug-containing beads, granules, pellets, particles or tablet with a coating material, preferably a polymeric material. Particularly preferred coating materials comprise bioerodible, gradually hydrolysable, gradually water soluble, or water-insoluble, enzymatic degradable and/or pH dependant polymers or may be conventional enteric materials. The coating weight, type or relative amount of coating material may be readily determined by those skilled in the art by evaluating individual release profiles for tablets, beads and granules prepared with different quantities of various coating materials.
Suitable coating materials for effecting delayed release include, but are not limited to, cellulosic polymers such as hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose acetate succinate, hydroxypropylmethyl cellulose phthalate, methylcellulose, ethyl cellulose, cellulose acetate, cellulose acetate phthalate, cellulose acetate trimellitate and carboxymethylcellulose sodium; acrylic acid polymers and copolymers, preferably formed from acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate and/or ethyl methacrylate, and other methacrylic resins that are commercially available under the tradename Eudragit® (Rohm Pharma; Westerstadt, Germany), including Eudragit® L30D-55 and L100-55 (soluble at pH 5.5 and above), Eudragit® L-100 (soluble at pH 6.0 and above), Eudragit® S (soluble at pH 7.0 and above, as a result of a higher degree of esterification), and Eudragits® NE, RL and RS (water-insoluble polymers having different degrees of permeability and expandability); vinyl polymers and copolymers such
as polyvinyl pyrrolidone, vinyl acetate, vinylacetate phthalate, vinylacetate crotonic acid copolymer, and ethylene-vinyl acetate copolymer; enzymatically degradable polymers such as azo polymers, pectin, chitosan, arabinogalactose, amylase, chondroitin sulfate, dextran, galactomannan, xylan and guar gum, locust-bean gum,gum tragacanth and Karaya gum; and shellac. Combinations of different coating materials may also be used. Multi-layer coatings using different polymers may also be applied.
Coating layer may optionally comprise further appropriate ingredients which improve the property of coating layers, such ingredients include but are not limited to fillers, plasticizers, anti-adhesive, pigments, coloring agents, stabilizing agents, surfactants, pore formers and the like.
In another embodiment a delayed release tablet may be formulated by dispersing the drug within a matrix of a suitable material such a hydrophilic polymer or a fatty compound. The hydrophilic polymers may be comprised of polymers or copolymers of cellulose, cellulose ester, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, and vinyl or enzymatically degradable polymers or copolymers as described above. These hydrophilic polymers are particularly useful for providing a delayed release matrix. Fatty compounds for use as a matrix material include, but are not limited to, waxes (e.g. carnauba wax) and glycerol tristearate. Once the active ingredient is mixed with the matrix material, the mixture can be compressed into tablets.
The objective of this invention to provide a once-a-day tacrolimus composition with both improved dissolution/bioavailability and faster action has been achieved by administering tacrolimus to mammals in timed pulsatile release manner providing release of drug in predetermine time interval (s). In accordance herewith, in preferred embodiments, the present invention provides pharmaceutical composition comprising tacrolimus and/or its pharmaceutically acceptable salts thereof, together with pharmaceutically acceptable excipients, wherein the first effective amount of tacrolimus is released immediately to elicit pharmacological response of tacrolimus and second amount of tacrolimus is released after a predetermined release-free interval or as defined earlier an interval of "substantially no release". The second amount of tacrolimus released in the late part of intestine may reduce drug related gastrointestinal tract related side effect as well as the relatively high degree of metabolism in the proximal part of gastrointestinal tract (CYP3A mediated metabolism).
EXAMPLES: The following non-limiting examples illustrate an embodiment of the invention and should not be construed to limit the scope of the invention. Any modifications of the method of invention are within the spirit or scope of the invention.
Dosage forms (Formula A and Formula B) were prepared containing immediate release component and modified release component as per the invention. The steps involved dissolving vitamin E TPGS, tacrolimus and glycerol mono-oleate in isopropyl alcohol and coating it on non-pareil seeds. These obtained pellets were divided into two parts, one part, which formed the immediate release dosage unit, was further coated with a film forming polymer solution and the second part, which formed the delayed release dosage unit, were
coated with an enteric polymer solution using the composition as given in Table 1, using a suitable coating equipment. Pellets of immediate release and modified release components corresponding to their desired amount were then filled into capsules.
Part 1: Immediate release Dosage Unit
Sr. No. Ingredients Formula A Quantity (mg/Cap) Formula B Quantity (mg/Cap)
1 Tacrolimus 1.75 2.50
2 Isopropyl alcohol 28.69 40.98
3 Vitamin E TPGS 26.52 37.88
4 Glycerol monooleate 10.03 14.33
5 Non-pareil seeds 196.35 280.51
6 Aerosil 200 10.33 14.76
Drug Loaded pellets 245.00 mg 390.96
7 Hydroxypropylmethylcellulose 5.00 7.81
8 Purified water 45.00 64.28
Part 2: Delayed Release Dosage Unit
1 Tacrolimus 3.25 2.50
2 Isopropyl alcohol 53.28 40.98
3 Vitamin E TPGS 49.25 37.88
4 Glycerol monooleate 18.63 14.33
5 Non-pareil seeds (#16/18) 361.048 280.51
6 Aerosil 200 17.423 14.76
Sub-total 450.00 mg 390.96
7 Methacrylic acid co-polymer 60.92 76.41
8 Triethyl citrate 15.50 3.34
9 Talc 33.56 -
10 Acetone 316.81 -
11 Isopropyl alcohol 625.88 -
12 Purified water 55.38 151.7
Sub-total (Coating) 110.0 mg 79.75
Dated this 29th of March 2007
|Indian Patent Application Number
|PG Journal Number
|Date of Filing
|Name of Patentee
|PANACEA BIOTEC LIMITED
|201 SAMARPAN COMPLEX, NEW LINK ROAD CHAKALA ANDHERI (EAST), MUMBAI-400099,
|PCT International Classification Number
|PCT International Application Number
|PCT International Filing date