Title of Invention

STABILISED PHARMACEUTICAL COMPOSITIONS ON THE BASIS OF POLYOXYETHYLATED CASTOR OIL AND METHOD FOR MANUFACTURING THE SAME

Abstract Stabilised pharmaceutical composition comprising a pharmaceutical^ active substance and a solvent system comprising a polar organic solvent and a solubilising agent, wherein the agent is a polyoxyethylated castor oil treated with an absorbent, namely silica gel or aluminosilicate to reduce the content of polar impurities including acidic compounds, characterized in that both the content of basic compounds is less than 0.6 x TO6 gram equivalents/ml and the content of acidic compounds is less than 0.06 mass % based on the mass of the polyoxyethylated castor oil.
Full Text FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION (See Section 10, rule 13)
STABILISED PHARMACEUTICAL COMPOSITIONS ON THE BASIS OF POLYOXYETHYLATED CASTOR OIL AND METHOD FOR MANUFACTURING THE SAME
PLIVA-LACHEMA A.S of KARASEK 1, 621 33 BRNO CZECH REPUBLIC, CZECH Company
The following specification particularly describes the nature of the invention and the manner in which it is to be performed : -

Stabilised pharmaceutical compositions on the basis of polyoxyethylated castor oil and method for manu¬facturing the same
Description
The invention relates to a stabilised pharmaceuti¬cal composition comprising a phantiaceutically ac¬tive substance poorly soluble in water, a solubi-lising agent with a low content of both basic and acidic compounds and a polar organic solvent, in particular a stabilised injection concentrate, methods for preparing such stabilised pharmaceuti¬cal compositions and the use of a solubilising agent with a low content of both basic and acidic compounds to stabilise pharmaceutical compositions for pharmaceutically active substances.
For the preparation of pharmaceutical compositions a suitable solvent or carrier system is required in order to disperse the pharmaceutically active agent so that the composition can be administered to a patient. The solvent must be capable of solubiliz-ing or dispersing a therapeutically effective amount of the active agent to produce an effective composition. However, many pharmaceutically active compounds are not sufficiently soluble in solvents such as water. Another problem is that numerous pharmaceutical agents are unstable after dilution to infusion solutions or they exhibit degradation and loss of activity during storage in solvent sys¬tems. The low solubility and the proneness to deg¬radation substantially limit the use of these phar¬maceutically active compounds in actual therapy.

Examples of pharmaceutically active compounds which are poorly soluble in water and prone to degrada¬tion during storage are the antineoplastic agents paclitaxel and camptothecin derivatives.
To overcome the limitations of the solvent, in par¬ticular water, to solubilize pharmaceutically ac¬tive agents, mixtures of two or more solvents are used. Such co-solvent systems comprise advanta¬geously non-ionogenic solubilisers in combination with a suitable polar solvent. Such combined sys¬tems assure sufficient solubility of otherwise poorly water-soluble active agents both in liquid concentrates for injection and in infusion solu¬tions obtained after dilution of the former. In such combined systems, ethanol is - used frequently as the polar solvent and polyoxyethylated castor oils as solubiliser. A polyoxyethylated castor oil of standard quality is commercially available from BASF under the trade mark Cremophor EL. Cremophor EL is chemically a polyoxyethylated glycerol triricinoleate. A particular useful co-solvent sys¬tem is a 50:50 mixture of ethanol and Cremophor EL, which can used for many active substances including paclitaxel or camptothecin derivatives that are poorly soluble in water.
The use of Cremophor EL as solubilizing agent in pharmaceutical compositions is associated with cer¬tain advantages, as shown by the patent application WO 91/02531. The document describes that Cremophor EL is capable of reversing the multi-drug resis¬tance phenotype of a tumour cell line without al¬tering the drug sensitivity of the parent cell line

and can support haemopoiesis. Therefore Cremo-phor/ethanol systems are in particular suitable for the preparation of pharmaceutical compositions, in particular those formulated for the treatment of oncologic diseases.
Furthermore, possible undesirable adverse responses of an organism to Cremophor can easily be avoided by a pre-medication with steroids and antagonists of Hi and H2-receptors.
However, a main disadvantage of Cremophor EL is the high content of basic compounds. The basic impuri¬ties of Cremophor EL result in a continuously re¬duced stability and deteriorating quality of the pharmaceutical compositions until expiration date, whereby the content of active substance decreases and the content of potentially toxic decomposition products of the active substance and other compo¬nents of the composition increases. Therefore, a number of recent patent documents relate to methods for stabilising pharmaceutical compositions com¬prising paclitaxel and polyoxyethylated castor oil.
Patent applications WO 94/12030 and WO 94/12031 disclose pharmaceutical compositions comprising pa¬clitaxel and a polyoxyethylated castor oil such as Cremophor EL which are stabilised by the adjustment of the pH of the composition to a value of less than 8.1. For the adjustment of pH inorganic acids, e.g. hydrochloric acid, sulphuric acid, nitric acid, or low molecular organic acids, advanta¬geously acetic acid or citric acid are used. The stabilising effects of acids are shown by a com-

parison of otherwise identical compositions. The content of taxol in a composition formulated with Cremophor EL, but without an acid (pH of 9.1) was 86,7% after 7 days at 40°C. In contrast, the con¬tent of taxol in a composition, whose pH was ad¬justed by the addition of citric acid to 6.2, was 96,6% after 7 days. A composition whose pH was ad¬justed by the addition of acetic acid to 6.7, ex¬hibited a taxol content of 97,5% after 7 days.
Patent application WO 94/12198 discloses a pharma¬ceutical composition comprising taxol, a solubilis-ing agent, advantageously a polyoxyethylated castor oil, an organic solvent, advantageously ethanol, and an acid that adjusts the pH of the composition to a value of less than 8.1. The pH can be adjusted essentially by the same acids as disclosed in the above mentioned patent applications WO 94/12030 and WO 94/12031.
EP 0 645 145 Bl describes a solvent system suitable for preparing a stabilised composition comprising a pharmaceutical compound. The solvent system com¬prises ethanol and a non-ionic solubilising agent, such as a polyoxyethylated oil, treated to reduce the carboxylate anion content to a sufficiently low concentration in order to minimize the decomposi¬tion of the pharmaceutical agent. The co-solvent system described is particularly suitable for use with pharmaceutical compounds such as paclitaxel, camptothecin and derivatives thereof that exhibit decomposition which is catalysed by carboxylate anions. According to this document the carboxylate anion content of the solvent can be reduced by

passing the polyoxyethylated oil such as Cremophor EL through a chromatography column of aluminium ox¬ide, whereby aluminium oxide efficiently adsorbs the carboxylate anions. The carboxylate content can also be reduced VY the addition of an acid, such as
of paclitaxel containing processed Cremophor EL and thus having a reduced carboxylate anion content are more stable thafl compositions containing unproc¬essed Cremophor I5L-
US patent 5,925,776 describes polyethoxylated cas¬tor oil with a l0w cation content, along with meth¬ods for lowering the cation content in polyethoxy¬lated castor oil The cations of interest, for ex¬ample Al3+, K+, Ca2+ and Na+, can be removed by a pretreatment of the polyethoxylated castor oil, which is preferably Cremophor EL, with a strong cationic exchange resin. The low cationic content polyethoxylated castor oil can be utilized to pre¬pare formulationS of agents which were found to be sensitive to commercially available polyethoxylated castor oil, such as diclofenac and paclitaxel. For¬mulations of such agents prepared with low cationic content polyethoxylated castor oil are found to have improved stability against active agent degra¬dation. However, a main disadvantage of the method described is based on the fact that there is a risk that the strong ion-exchange resin used to lower the cation content, can lead to a partial decompo¬sition (splitting) of the polyoxyethylated castor oil, especially under the low pH conditions used, leading to an increased amount of free fatty acids.

Nowadays a processed polyoxyethylated castor oil is commercially available under the trade name Cremo-phor EL-P. Cremophor EL-P which has a lower content of basic compounds in comparison to Cremophor EL can be used for the preparation of a relatively stable composition of paclitaxel.
It is apparent from the prior art that the content of basic compounds in polyoxyethylated castor oil, particularly of carboxylate anions, is one of the main reasons for the instability of paclitaxel and similar antineoplastic compounds in formulations based on polyoxyethylated castor oil. All the rele¬vant procedures solve, in different ways, the same problem, namely to decrease the content of basic compounds in the polyoxyethylated castor oil or in the final pharmaceutical composition comprising the polyoxyethylated castor oil. None of the prior art patent documents provides any procedure that could further improve the stability of the above-mentioned pharmaceutical substances in polyoxyethy¬lated castor oil once the content of basic com¬pounds was decreased to a value equal to or less than 0,6 x 10"6 gram equivalents/ml. Thus, there is a continuing need in the art for stabilised pharma¬ceutical compositions comprising an active agent which is poorly soluble in water.
Thus, the technical problem underlying the present invention is to provide a stabilised pharmaceutical composition which is especially suited for pharma-ceutically active agents such as paclitaxel or camptothecin which shows a further improved stabil¬ity in comparison to pharmaceutical compositions

described in the prior art and prevents more effi¬ciently the degradation of the active substance.
The present invention solves the technical problem by providing a stabilised pharmaceutical composi¬tion comprising a pharmaceutically active substance and a solvent system comprising a polar organic solvent and a solubilising agent, wherein the agent is a polyoxyethylated castor oil, characterised in that both the content of basic compounds is less than 0,6 x 10"6 gram equivalents/ml and the content of acidic compounds is equal to or less than 0,06 mass % based on the mass of the polyoxethylated castor oil. The present invention also solves the technical problem by providing methods for prepar¬ing stabilised pharmaceutical compositions whereby polyoxyethylated castor oil used as solubilising agent is pre-treated with an adsorbent in order to reduce the content of polar impurities, especially the content of acidic substances, and by the use of a solubilising agent with a low content of basic compounds and a low content of acidic compounds to stabilise a pharmaceutical composition comprising a pharmaceutically active substance which is poorly soluble in water.
Contrary to the existing technical prejudice, that the stability of pharmaceutically active compounds such as paclitaxel or camptothecin in a co-solvent system comprising a polar organic solvent and a solubiliser, such as a polyoxyethylated castor oil, depends only on the presence of basic compounds, the inventors of the present invention have sur¬prisingly found that acidic compounds present in

the composition, in particular in the solubilizing agent, also have a great impact on the stability of such pharmaceutically active compounds.
For example, the commercially available Cremophor EL-P characterized by a reduced content of basic compounds, however, contains impurities such as fatty acids and the oxyethylated forms thereof, polyethylenglycol diricinoleate and small amounts of corresponding free glycols. Upon treatment of Cremophor EL-P with a suitable adsorbing agent to remove these acidic compounds, pharmaceutical com¬positions comprising such pre-treated Cremophor EL-P exhibit a greatly enhanced stability of the phar¬maceutically active agents in comparison with com¬positions prepared with untreated Cremophor EL-P as shown by the determination of decomposition prod¬ucts of pharmaceutically active compounds in the compositions formed after a long-term storage.
Thus, the analysis of pharmaceutical compositions of paclitaxel prepared with treated or untreated Cremophor EL-P has revealed that in compositions with treated Cremophor EL-P after 3 month storage the amounts of the main decomposition products such as baccatin III, 10-deacetyl-paclitaxel, 10-deacetyl-7-epi-paclitaxel, 7-epi-paclitaxel and cephalomannin are much smaller than in compositions prepared with untreated Cremophor EL-P. Also, in¬jections of camptothecin prepared with treated Cre¬mophor EL-P exhibit an improved stability, since after 14 days these injections contain more non-decomposed camptothecin than camptothecin injec¬tions prepared with untreated Cremophor EL-P.

In summary, these results obtained according to the invention confirm that also acidic compounds pre¬sent in the solubilizing agent contribute to the decomposition of active agents such as paclitaxel or camptothecin. The less the content of both basic and acidic compounds in the composition with a polyoxyethylated castor oil, the more stable the pharmaceutically active compound in it.
Therefore, according to the invention a further im¬provement of the stability of pharmaceutically ac¬tive compounds in a co-solvent system comprising a polar organic solvent and a solubiliser, in par¬ticular a polyoxyethylated castor oil with a low content of basic compounds such as Cremophor EL-P, can be obtained by decreasing the content of acidic compounds to a value equal to or less than 0.06 mass % based on the mass of the polyoxyethylated castor oil. According to the invention in particu¬lar the content of free fatty acids such as rici-noleic acid, oleic acid and palmitic acid must be less than 0.06 mass %.
The inventive stabilised pharmaceutical composition is in particular suited for pharmaceutically active agents which exhibit degradation and loss of acti¬vity during storage, e.g. paclitaxel and camptothe¬cin and derivatives thereof. According to the in¬vention the formation of some decomposition com¬pounds known can be caused not only by basic compo¬nents of the solubilizing agent but also by acidic components thereof.

The present invention therefore relates to a phar¬maceutical composition with improved stability com¬prising a pharmaceutically active compound and a solvent system comprising a polar organic solvent and a solubiliser, wherein the solubiliser is a polyoxyethylated castor oil said composition being characterised by a low content of basic compounds, particularly carboxylate anions, equal to or less than 0,6 x 1CT6 gram equivalents/ml and by a low content of acidic compounds which is equal to or less than 0.06 mass % based on the mass of the polyoxyethylated castor oil.
According to the invention, the term "pharmaceuti¬cal composition" refers to a mixture of substances which is used for diagnostic, therapeutic or pro¬phylactic purposes, that is which supports or re¬stores the health of a human or animal body, and which comprises at least a natural or synthetically generated active agent, inducing the desired thera¬peutic effect. The pharmaceutical composition can comprise one or more pharmaceutically acceptable excipients and additives usually employed in the art. According to the invention, a pharmaceutical composition which is "stabilised" or which has "im¬proved stability" is a composition in which the de¬composition of the active agent is prevented or at least delayed, so that even after long term storage more than 90%, in particular more than 95%, pref¬erably more than 97%, most preferably more than 99% of the active agent have not undergone a decomposi¬tion.

In a particular preferred embodiment of the inven¬tion the stabilised pharmaceutical composition has the form of an injection comprising a pharmaceuti-cally active agent. "Injections" are sterile liquid dosage forms including solutions, suspensions or emulsions for parenteral administration. Such liq¬uid dosage form may also contain preserving, wet¬ting, emulsifying and dispersing agents. Injections may be sterilized by, for example, filtration through a bacteria and/or other pathogens retaining filters, by incorporating sterilising agents into the compositions and/or by irradiating the composi¬tions. They can also be manufactured using sterile components immediately before use.
The term "pharmaceutically active agent" or "active agent" refers to any compound or derivate thereof which can affect or recognise biological cells or parts thereof, in particular cell organelles or cellular components, by an direct or indirect in¬teraction with cellular macromolecules whereby a number of functional changes is induced leading to a biological effect in the body. In particular, such active agents are diagnostics or therapeutics. In the context of the present invention the term "active agents" or "pharmaceutical^ active agents" refers in particular to therapeutics, i.e. sub¬stances which can be administered as a preventive measure or during the course of a disease, disorder or condition to organisms in need of such a treat¬ment in order to prevent or to reduce or to abolish a disease, disorder or condition.

In a preferred embodiment of the invention, the stabilised pharmaceutical composition, in particu¬lar injection, comprises an pharmaceutically active agent that is poorly soluble in water and/or sensi¬tive towards degradation during storage. According to the invention the pharmaceutically active agent is preferably selected from the group consisting of paclitaxel, camptothecin and derivatives thereof.
Therefore, in a particular preferred embodiment of the invention the pharmaceutical composition com¬prises paclitaxel as pharmaceutically active agent.
Paclitaxel is an pharmaceutically active agent with antineoplastic activity, which is commercially a-vailable from Bristol-Myers-Squibb under the trade name TAXOL. Paclitaxel is believed to function as a mitotic spindly poison and as a potent inhibitor for cell replication. Paclitaxel is a compound of formula (I):

During storage the main products of paclitaxel de¬composition are baccatin III, 10-deacetyl-paclitaxel, 10-deacetyl-7-epi-paclitaxel, 7-epi-paclitaxel and cephalomannin. As known in the art,

the formation of these decomposition products of paclitaxel can be catalysed by basic compounds. Ac¬cording to the invention the formation of these paclitaxel decomposition products can also be cata¬lysed by acidic compounds.
In another preferred embodiment of the invention the pharmaceutical composition comprises camptothe-cin as pharmaceutically active agent.
Camptothecin is a pharmaceutically active substance of formula (II):

(II).
Camptothecin and derivatives thereof (irinotecan, topotecan etc.) also exhibit an important antineo¬plastic activity. The therapeutic activity of these compounds is conditioned by the existence of a closed lactone ring of the given structure. The lactone ring may be split by solvolysis into an open-chain carboxyl form, said form however being far less therapeutically effective. Such a solvoly¬sis can be induced by both bases and acids present in the composition, in particular in the solubi-lizer.
The term "derivative thereof" refers to non-toxic functional equivalents or derivatives of paclitaxel

or camptothecin, which can be obtained by substitu¬tion of atoms or molecular groups or bonds of the paclitaxel or camptothecin molecule, whereby the basic structure is not changed, and which differ from the structure of paclitaxel or camptothecin in at least one position.
The term "solvent" refers to an inorganic or or¬ganic fluid in which another liquid or solid com¬pound can be solved. A prerequisite of an solvent is that neither the solvent nor the substance to be solved undergo an chemical change. A physical pre¬condition for an solvent is the presence of polar or non-polar residues. A "polar organic solvent" therefore refers to an organic solvent with polar residues.
In a preferred embodiment of the invention the po¬lar organic solvent is ethanol.
The term "solubiliser" or "solubilizing agent" re¬fers to substances which render a compound which is poorly soluble or insoluble in a certain solvent, soluble or emulsifiable in that solvent. Optionally a solubiliser can be a surface active agent. An ex¬ample of an solubilizer is polyoxyethylated castor oil. Polyoxyethylated castor oil, for example Cre-mophor EL, is chemically a polyoxyethylated glyc¬erol triricinoleate. Cremophor EL is characterized by the big content of basic compounds, in particu¬lar carboxylate anions, which affect the stability of pharmaceutical compositions.

According to the invention the polyoxyethylated castor oil used as solubilizer has a low content of basic compounds, such as carboxylate anions, of less than 0,6 x 10"6 gram equivalents/ml. In a par¬ticular preferred embodiment of the invention the polyoxyethylated castor oil with such a low content of basic compounds, used as solubilizer, is Cremo-phor EL-P prepared according to prior art. As impu¬rities, the product contains fatty acids and its oxyethylated forms, polyethylenglycol diricinoleate and small amounts of corresponding free glycols. However, Cremophor EL-P has a high content of free fatty acids, in particular C12 to C18 fatty acids of equal to or less than 1.0%. Cremophor EL-P compri¬ses approx. 0,2% ricinoleic acid and approximately 0.1% oleic acid and 0.1% palmitic acid. The amount of ricinoleic acid of 0.2% corresponds to approxi¬mately 50% of the stoichiometric amount relative to paclitaxel present in the composition and is there¬fore relatively high.
In a more preferred embodiment of the invention the content of free fatty acids is less than 0.06 mass % based on the mass of the polyoxyethylated castor oil. In another particular preferred embodiment of the invention the content of both free oleic acid and palmitic acid must be equal to or less than 0,01 mass % based on the mass of the polyoxyethy¬lated castor oil.
A concentration of carboxylate anions of less than or equal to 0,6 x 10"6 gram equivalents/ml can be determined as specified in US patent 5,504,102, in particular by indirect measurement by adding acid,

in particular HC1. A direct measurement of fatty acids is possible by the GC method after derivati-sation of these compounds.
According to the invention the content of acidic compounds in the composition, in particular in solubilizer of the co-solvent system, can be low¬ered by a number of methods.
In a preferred embodiment advantageously the con¬tent of polar impurities, in particular acidic com¬pounds in the solubilizer, i.e. the polyoxyethy¬lated castor oil, is reduced by treatment of the polyoxyethylated castor oil with an adsorbent. Ac¬cording to the present invention an "adsorbent" is usually a solid substance, which is capable of se¬lectively enriching certain components of a mixture at its boundary surface due to its large surface.
A preferred embodiment of the present invention therefore relates to a stabilised pharmaceutical composition wherein the polyoxyethylated castor oil is a polyoxyethylated castor oil treated with an adsorbent. Preferably, the adsorbent used to reduce the content of acidic compounds is silica gel or aluminosilicate. In a particular preferred embodi¬ment of the invention the polyoxyethylated castor oil is Cremophor EL-P having a low content of basic compounds and treated with silica gel (5 to 10 mass%) at a moderate temperature, preferably in the range of 40 to 60°C, in particular 50°C. Silica gel is a slightly acidic and polar adsorbent which eliminates polar impurities including acidic com¬pounds in a simple and effective way. By the treat-

ment of polyoxyethylated castor oils, such as Cre-mophor EL-P, with such an adsorbent the content of acidic compounds can easily be reduced to amounts of less than 0,06%.
The present invention relates also to methods for preparing stabilised pharmaceutical compositions comprising a pharmaceutically active substance in a solvent system comprising a polar solvent and a solubilising agent, wherein the solubilising agent is a polyoxyethylated castor oil, comprising the steps of treating a polyoxyethylated castor oil with a low content of a basic compound with an ad¬sorbent in order to reduce the content of polar im¬purities and mixing the treated polyoxyethylated castor oil with a certain amount of the polar or-gainic solvent and a certain amount of the pharma-ceutically active substance.
In a preferred embodiment the polyoxyethylated cas¬tor oil to be treated comprises basic compounds in a content of less than 0,6 x 10"6 gram equivalents based on the mass of the polyoxyethylated castor oil. In a particular preferred embodiment the poly¬oxyethylated castor oil with a reduced amount of basic compounds to be treated is Cremophor EL-P.
According to the invention the polyoxyethylated castor oil with a low or reduced content of a basic compound is treated with an adsorbent to reduce the content of polar impurities, in particular acidic substances such as free fatty acids.

In a preferred embodiment of the inventive method, the adsorbent used to reduce the amount of acidic substances is aluminosilicate or silica gel. In a particularly preferred embodiment Cremophor EL-P is treated with silica gel (5 to 10 mass%) at a moder¬ate temperature, preferably in the range of 40 to 60°C, in particular 50 °C. After treatment with the adsorbent Cremophor EL-P has advantageously a con¬tent of acidic compounds of equal to or less than 0,06 mass% based on the mass of the polyoxyethy¬lated castor oil. Preferably Cremophor EL-P com¬prises ricinoleic acid in a content of equal to or less than 0,05 mass% and oleic acid and palmitic acid in a content of equal to or less than 0,01 mass% based on the mass of the polyoxyethylated castor oil.
In a preferred embodiment of the inventive method the polar solvent used for the preparation of the stabilised pharmaceutical composition is ethanol. The polyoxyethylated castor oil treated by the ad¬sorbent is preferably mixed with ethanol in a ratio of 1:1.
In another preferred embodiment of the inventive method, the pharmaceutically active substance is poorly soluble in water. In particular, the pharma¬ceutically active substance is selected from the group consisting of paclitaxel, camptothecin and their derivatives.
Another aspect of the invention relates to the use of a solubilising agent with a low content of basic compounds and a low content of acidic compounds to

stabilise a pharmaceutical composition comprising a pharmaceutically active substance which is poorly soluble in water. In a preferred embodiment the solubilising agent is polyoxyethylated castor oil with a low content of basic compounds, in particu¬lar of less than 0,6 x 10"6 gram equivalents based on the mass of the polyoxyethylated castor oil, which is treated with an adsorbent to reduce the amount in particular of the acidic compounds such as free fatty acids, in particular ricinoleic acid, oleic acid and palmitic acid. In a particular pre¬ferred embodiment the polyoxyethylated castor oil comprising a low content of basic compounds and treated with the adsorbent is Cremophor EL-P. Pref¬erably, the polyoxyethylated castor oil treated with the adsorbent such a silica gel or alumi-nosilicate and used for stabilising pharmaceutical compositions has a content of acidic compounds less than 0,6 mass % based on the mass of the poly¬oxyethylated castor oil. In another embodiment the solubilising agent with a low content of basic com¬pounds and a low content of acidic compounds is used to stabilise pharmaceutical compositions wherein the pharmaceutically active substance is selected from the group consisting of paclitaxel, camptothecin and their derivatives.
The invention will be further explained by the fol¬lowing examples. The examples are for illustrative purposes only and shall by no means limit the scope of the invention.

Examples
Example 1; Description of analytical methods
1. Determination of the content of free fatty ac¬
ids in polyoxyethylated castor oil by GC
method
The content of free fatty acids was determined by the BASF test method 0330/Ole. Free fatty acids in polyoxyethylated castor oil were converted to vola¬tile silylester compounds by means of N-methyl-N-trimethylsilyltrifluoracetamide. Volatile silyles¬ter compounds were analysed by the GC method (cap¬illary column HP-5; 30 m 0.32 mm ID; 0.25 urn; FID detector ) . The content was quantified by internal standard method with methylmargarate.
The content of free fatty acids in Cremophor EL-P, as determined by the BASF GC method was as follows:
Ricinoleic acid 0,07% oleic acid 0,02% palmitic acid 0,02%
2. Determination of the content of paclitaxel and
related compounds in the composition by HPLC
The standard HPLC method described in Pharmacopoe-ial Forum, Vol.24, No.6, Nov.-Dec.1998, p.7167 was used.

Example 2: Preparation of Cremophor EL-P with low acidic compound content (LAC)
Starting materials:
Cremophor EL-P(BASF): water content 0,3%; pH of 10% aqueous extract 6,3; total content of free fatty acids: 0,18%;
Silica gel: Kieselgel 60, 0.063-0.200 mm
Cremophor EL-P (3 kg) and 5 mass% of silica gel were stirred under dry nitrogen 2 hours at 50°C. Cremophor was then filtered. This process was re¬peated once again. The yield of Cremophor EL-P-LAC was almost 90%. The total content of free fatty ac¬ids in Cremophor EL-P-LAC was 0.06 mass%, the con¬tent of ricinoleic acid was 0.05 mass%, the content of oleic acid and palmitic acid was less than 0.01 mass% respectively. A 10% solution of Cremophor EL-P-LAC in water had a pH value of 6,3. This shows that the removal of fatty acids did not alter the pH value in Cremophor in comparison to Cremophor EL-P.
Example 3: Preparation of paclitaxel injections
Starting materials:
Ethanol: water content As solubilising agents Cremophor EL-P (BASF) and Cremophor EL-P from Example 2 were used.

Cremophor EL-P-LAC: Cremophor EL-P-LAC from Example 2 was used.
Paclitaxel API (by SUAN Pharma): paclitaxel, con¬tent 99,73 mass% (determined by high performance liquid chromatography)
Under GMP conditions, a solution of Cremophor and ethanol in volume ratio 1:1 was prepared, with a paclitaxel concentration of 6 mg/ml of the solu¬tion. The resulting solution was filtered under sterile conditions through a filter with a porosity of 0,2 mm. Volumes of 5ml were filled into glass vials for antibiotics of the first hydrolytic class. The vials were closed under nitrogen atmos¬phere with Omniflex rubber stoppers and aluminium seal.
Example 4: Stability study of paclitaxel composi¬tions
The stability study was performed by subjecting the injections to a temperature of 40°C at 75% R.H. for three months. The compositions were analysed by validated HPLC method. The results are summarised in Table 1.

Table 1: The three months stability study of pacli¬taxel injections at 40°C and 75% R.H.

Compound Time 0 % injections
Cremophor EL-P
3 month3
t injections
Cremophor EL-P-LAC
3 months
%
Paclitaxel 99.66 98.27 99.52
Baccatim III non detec¬table 0.09 non detect
10-deacetyltaxel non de¬tectable 0.35 0.07
7-epi-taxel 0.03 0.10 0.07
7-epi-10-deacetyltaxel 0.01 0.04 0.03
Cephalomannin 0.15 0.29 0.20
unknown impurities above 0.1* 0 2 0
total relative impurities 0.34 1.73 0.48
The compositions of both injections were practi-5 cally identical in time 0.
The results in Table 1 demonstrate the superior stability of paclitaxel in the composition with polyoxyethylated castor oil and ethanol according to the present invention, characterised by low con-

tents of both basic and acidic compounds. Baccatin III is the main impurity from basic splitting and is negligible in both injections. The results show, however, that the formation of undesired 10-deacetyltaxel, 7-epi-taxel, cephalomannin and at least two unknown impurities is supported by the presence of free acids in compositions, since com¬positions comprising Cremophor EL-P-LAC show re¬duced amounts of these compounds after 3 months.
Pharmaceutical composition based on a polyoxyethy-lated castor oil with low content of both basic and acidic compounds according to present invention may be used not only for paclitaxel, but also for other pharmaceutical^ active compounds that are poorly soluble in water and/or susceptible to a degrada¬tion during storage. For instance, the composition of the invention can also be applied to pharmaceu¬tical compositions of camptothecin and derivatives thereof as shown in the following Example 5.
Example 5: Preparation of camptothecin compositions
In this example Cremophor EL-P and Cremophor EL-P-LAC from Example 2 were used as solubilising agents. Under GMP conditions, 600mg of 7-ethyl-10-hydroxycamptothecin (purity 99.2 mass% as deter¬mined by high performance liquid chromatography) were dissolved in 50 ml of ethanol at 50°C. The so¬lution was cooled to 21°C and 50 ml of the respec¬tive Cremophor was added to the composition. The resulted solution was filtered under sterile condi¬tions through a filter of 0.2 urn porosity and was filled in 5 ml volumes into glass antibiotic vials

of 1st hydrolytic class. The vials were closed un¬der nitrogen atmosphere with Omniflex rubber stop¬pers and aluminium seal.
The stability study of injections was performed by 5 subjecting them to a temperature of 50°C and 75% R.H. for 14 days. The content of 7-ethyl-10-hydroxycamptothecin in the injections was deter¬mined by a standardised method of high performance liquid chromatography. The obtained results are 10 shown in the following Table 2.
Table 2: 14 days stability study of 7-ethyl-10-hydroxycamptothecin injections at 50°C and 75 % R.H.

Injections 7-ethyl-10- hydroxycamp-tothecin content, %
Injections from Cremophor EL-P-LAC 98.2
Injections from Cremophor EL-P 97,2
15 It is apparent from the results presented that the invention may also be advantageously used for pro¬viding stable pharmaceutical compositions compris¬ing camptothecin and/or derivatives thereof as an active substance.
20

We Claim:
1. Stabilised pharmaceutical composition comprising a pharmaceutical^ active substance and a solvent system comprising a polar organic solvent and a solubilising agent, wherein the agent is a polyoxyethylated castor oil treated with an absorbent, namely silica gel or aluminosilicate to reduce the content of polar impurities including acidic compounds, characterized in that both the content of basic compounds is less than 0.6 x TO6 gram equivalents/ml and the content of acidic compounds is less than 0.06 mass % based on the mass of the polyoxyethylated castor oil.
2. The stabilised pharmaceutical composition as claimed in claim 1, wherein the polar organic solvent is ethanol.
3. The stabilised pharmaceutical composition as claimed in any one of claims 1 to 2, wherein the pharmaceutically active substance is an active substance which is poorly soluble in water and/or sensitive to degradation during storage.
4. The stabilised pharmaceutical composition as claimed in claim 3, wherein the pharmaceutically active compound is selected from the group consisting of paclitaxel, camptothecin and their derivatives.
5. Method for preparing a stabilized pharmaceutical composition comprising a pharmaceutically active substance in a solvent system comprising a polar solvent and a solubilising agent, wherein the solubilising agent is a polyoxyethylated castor oil comprising the steps of treating a polyoxyethylated castor oil, which comprises basic compounds in a content of less than 0.6 x 10-6 gram equivalents based on the mass of the polyoxyethylated castor oil with an absorbent, namely silica gel or aluminosilicate, in order to reduce the content of polar impurities, including acidic substances, whereby the content of acidic substances is reduced to

less than 0.06 mass % based on the mass of polyoxyethylated castor oil and mixing the treated polyoxyethylated castor oil with an amount of the polar organic solvent and an amount of the pharmaceutically active substance.
6. The method as claimed in claim 5, wherein the polyoxyethylated castor oil is Cremophor EL-P.
7. The method as claimed in any one of claims 5 to 6 wherein the polar solvent is ethanol.
8. The method as claimed in claim 7, wherein the treated polyoxyethylated castor oil is mixed with ethanol in a ratio of 1:1.
9. The method as claimed in any one of claims 5 to 8, wherein the pharmaceutically active substance is poorly soluble in water.
10. The method as claimed in claim 9, wherein the pharmaceutically active substance is selected from the group consisting of paclitaxel, camptothecin and their derivatives.
Dated this 1st day of November, 2004.


Documents:

614-mumnp-2004-cancelled pages(01-11-2004).pdf

614-mumnp-2004-claims(granted)-(01-11-2004).doc

614-mumnp-2004-claims(granted)-(01-11-2004).pdf

614-mumnp-2004-correspondence(10-02-2005).pdf

614-mumnp-2004-correspondence(ipo)-(09-02-2007).pdf

614-mumnp-2004-form 19(01-11-2004).pdf

614-mumnp-2004-form 1a(01-11-2004).pdf

614-mumnp-2004-form 1a(14-12-2004).pdf

614-mumnp-2004-form 2(granted)-(01-11-2004).doc

614-mumnp-2004-form 2(granted)-(01-11-2004).pdf

614-mumnp-2004-form 3(01-11-2004).pdf

614-mumnp-2004-form 3(10-03-2005).pdf

614-mumnp-2004-form 5(01-11-2004).pdf

614-mumnp-2004-form-pct-ipea-409(01-11-2004).pdf

614-mumnp-2004-form-pct-isa-210(01-11-2004).pdf

614-mumnp-2004-power of attorney(01-11-2004).pdf

614-mumnp-2004-power of attorney(10-03-2005).pdf


Patent Number 205892
Indian Patent Application Number 614/MUMNP/2004
PG Journal Number 28/2007
Publication Date 13-Jul-2007
Grant Date 12-Apr-2007
Date of Filing 01-Nov-2004
Name of Patentee PLIVA-LACHEMA A. S
Applicant Address KARASEK 1, 621 33 BRNO CZECH REPUBLIC,
Inventors:
# Inventor's Name Inventor's Address
1 KYSILKA, VIADIMIR DUHOVA 2, 62100 BRNO, CZECH REPUBLIC,
2 KUBAT MARTIN VALASSKA 5, 60200 BRNO, CZECH REPUBLIC.
3 ZATLOUKALOVA LIBUSE SUMAVSKA 36, 60200 BRNO, CZECH REPUBLIC.
4 ZALUDEK BOREK NOVOMESTSKA 19, 62100 BRNO, CZECH REPUBLIC.
5 POSPISILIK KAREL JEZKOVA 1, 63800 BRNO, CZECH REPUBLIC.
6 CIGANKOVA MARIE ODLEHLA 16, 62100 BRNO, CZECH REPUBLIC.
7 CIRKVA ALES SOSNOVA 5, 60200 BRNO, CZECH REPUBLIC.
PCT International Classification Number A61K47/44
PCT International Application Number PCT/EP03/05153
PCT International Filing date 2003-05-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 PV 2002-2027 2002-06-10 Czech Republic