This application is a continuation of U.S. patent application Ser. No. 11/391,897, filed Mar. 29, 2006. which is a continuation of U.S. patent application Ser. No. 11/093,626, filed Mar. 30, 2005, now U.S. Pat. No. 7,129,248, which claims priority to U.S. Provisional Application No. 60/651,778, filed Feb. 10, 2005, U.S. Provisional Application No. 60/648,625, filed Jan. 31, 2005, U.S. Provisional Application No. 60/620,072, filed Oct. 18, 2004, U.S. Provisional Application No. 60/601,534, filed Aug. 13, 2004, and U.S. Provisional Application No. 60/557,492, filed Mar. 30, 2004, all of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a process for reducing the amount of 14-hydroxycodeinone in an oxycodone hydrochloride preparation.

BACKGROUND OF THE INVENTION

Oxycodone is a semi-synthetic opioid analgesic that exerts an agonist effect at specific, saturable opioid receptors in the CNS and other tissues. In man, oxycodone may produce any of a variety of effects including analgesia.

Purdue Pharma L.P currently sells sustained-release oxycodone in dosage forms containing 10, 20, 40, and 80 mg oxycodone hydrochloride under the trade name OxyContinÂ®.

U.S. Pat. Nos. 5,266,331; 5,508,042; 5,549,912; and 5,656,295 disclose sustained release oxycodone formulations.

Thebaine, a compound derived from opium, although having no medicinal use in itself, is useful as a starting material in synthetic schemes for the production of oxycodone. In other schemes, codeine can be utilized as the starting material for the production of oxycodone. 14-hydroxycodeinone is the immediate precursor to oxycodone in these schemes.

Methods of producing thebaine or 14-hydroxy substituted opium derivatives have been reported, e.g. in U.S. Pat. Nos. 3,894,026 and 4,045,440.

The oxidation of codeine to codeinone, an initial step in the synthesis of opium derivatives has been reported in EP 0889045, U.S. Pat. No. 6,008,355 and in the J. Am. Chem. Soc., 1051, 73, 4001 (Findlay).

The reaction of codeinone to 14-hydroxycodeinone has been reported in U.S. Pat. No. 6,008,355 and in Tetrahedron 55, 1999 (Coop and Rice).

The methylation of codeinone to thebaine has been reported in Heterocycles, 1988, 49, 43-7 (Rice) and EP0889045.

U.S. Pat. No. 6,177,567 describes the hydrogenation of 14-hydroxycodeinone to oxycodone by reduction with diphenylsilane and Pd(Ph3P)/ZnCl2 or with sodium hypophosphite in conjunction with a Pd/C catalyst in aqueous acetic acid.

Krabnig et al. in â€œOptimization of the Synthesis of Oxycodone and 5-Methyloxycodoneâ€ Arch. Pharm. (1996), 329(6), (325-326) describes hydrogenating a solution of 14-hydroxycodeinone in glacial acetic acid with a Pdâ€”C-catalyst at 30 psi at the described conditions.

During the oxidation of thebaine to give 14-hydroxycodeinone, several overoxidized products are formed including 8,14-dihydroxy-7,8-dihydrocodeinone. In the production of oxycodone free base from the 14-hydroxycodeinone, the 8,14-dihydroxy-7,8-dihydrocodeinone is carried though the process. During conversion of the oxycodone free base to oxycodone hydrochloride, the impurity undergoes acid-catalyzed dehydration and is converted into 14-hydroxycodeinone. Thus, 14-hydroxycodeinone is present in the final oxycodone hydrochloride composition. Oxycodone hydrochloride API (active pharmaceutical ingredient) is available from a variety of manufacturers such as Johnson Matthey and Mallinckrodt. Current commercially-available oxycodone hydrochloride API, and oxycodone hydrochloride prepared by known procedures, have a level of 14-hydroxycodeinone of greater than 100 ppm.

There is a continuing need in the art to provide an oxycodone hydrochloride composition that contains reduced amounts of 14-hydroxycodeinone as compared to compositions known in the art.

All references cited herein are incorporated by reference in their entireties for all purposes.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of certain embodiments of the present invention to provide a process for reducing the 14-hydroxycodeinone in an oxycodone hydrochloride composition to an amount of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm.

It is an object of certain embodiments of the present invention to provide a process for reacting an oxycodone base composition with hydrochloric acid under conditions to produce an oxycodone hydrochloride composition having an amount of 14-hydroxycodeinone of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm.

It is a further object of certain embodiments of the present invention to provide an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm.

It is a further object of certain embodiments of the present invention to provide a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm by reacting an oxycodone base composition with hydrochloric acid under conditions suitable to promote dehydration of 8,14-dihydroxy-7,8-dihydrocodeinone to 14-hydroxycodeinone during salt formation and under reducing conditions so as to convert thel4-hydroxycodeinone to oxycodone.

In certain embodiments, the invention is directed to an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm comprising subjecting an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of greater than 100 ppm to hydrogenation to an extent that the amount of 14-hydroxycodeinone in the composition is reduced to an amount of less than less 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm.

In certain embodiments disclosed herein, the oxycodone composition having a 14-hydroxycodeinone level of less than 25 ppm can be subsequently hydrogenated to further decrease the amount of 14-hydroxycodeinone, e.g., from about 15 ppm to about 10 ppm or less.

In one embodiment, where the starting material is an oxycodone hydrochloride composition comprising 14-hydroxycodeinone in an amount of 100 ppm or higher, the final oxycodone hydrochloride composition has a 14-hydroxycodeinone level of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm. In another embodiment, where the starting material is an oxycodone hydrochloride composition comprising 14-hydroxycodeinone in an amount of between 15 ppm and 25 ppm, the final oxycodone hydrochloride composition has a 14-hydroxycodeinone level of less than about 10 ppm, or less than about 5 ppm. In another embodiment, where the starting material is an oxycodone hydrochloride composition comprising 14-hydroxycodeinone in an amount of between 10 ppm and 25 ppm, the final oxycodone hydrochloride composition has a 14-hydroxycodeinone level of less than about 5 ppm.

In certain embodiments of the present invention, the process for preparing the oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm comprises hydrogenating the starting material under reflux. In certain embodiments, the process further comprises recovering the resultant oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm comprising hydrogenating under reflux, a starting oxycodone hydrochloride composition having a 14-hydroxycodeinone level of greater than 100 ppm in a suitable solvent for a time sufficient to produce an oxycodone composition having a 14-hydroxycodeinone level of less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm; and recovering the oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm by crystallization and removal from the solvent (e.g., by filtration).

In certain embodiments, the oxycodone hydrochloride composition of the present invention has a lower limit of 0.25 ppm, 0.5 ppm, 1 ppm, 2 ppm or 5 ppm of 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising reacting in a suitable solvent an oxycodone base composition with hydrochloric acid in an amount greater than 1.0 molar equivalent as compared to the oxycodone base composition, the reacting step being performed under reducing conditions, to form an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone comprising hydrogenating a 14-hydroxycodeinone composition to obtain an oxycodone free base composition; converting the oxycodone free base composition to oxycodone hydrochloride; and hydrogenating the oxycodone hydrochloride to obtain an oxycodone composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone comprising hydrogenating a 14-hydroxycodeinone composition to obtain an oxycodone free base composition; converting the oxycodone free base composition to oxycodone hydrochloride; isolating the oxycodone hydrochloride; and hydrogenating the oxycodone hydrochloride to obtain an oxycodone composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone comprising oxidizing a thebaine composition to form 14-hydroxycodeinone composition, the oxidizing being performed at a suitable pH to minimize or eliminate the production of 8,14-dihydroxy-7,8-dihydrocodeinone in the 14-hydroxycodeinone composition; hydrogenating the 14-hydroxycodeinone composition to form an oxycodone base composition; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing 14-hydroxycodeinone comprising oxidizing a thebaine composition to form 14-hydroxycodeinone composition, the oxidizing being performed at a suitable pH to minimize or eliminate the production of 8,14-dihydroxy-7,8-dihydrocodeinone in the 14-hydroxycodeinone composition;

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition comprising reacting an oxycodone base composition with an acid having a higher pH than hydrochloric acid to form a corresponding acid addition salt of oxycodone, and converting the acid addition salt of oxycodone to oxycodone hydrochloride.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising contacting an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone with a substance that preferentially removes the 8,14-dihydroxy-7,8-dihydrocodeinone as compared to the oxycodone base; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising subjecting an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone to chromatographic separation to preferentially removes the 8,14-dihydroxy-7,8-dihydrocodeinone as compared to the oxycodone base; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising reacting in a suitable solvent an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone, with boronated polystyrene resin; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition comprising reacting in a suitable solvent an oxycodone base composition with boronated polystyrene resin; and converting the oxycodone base composition to an oxycodone hydrochloride composition.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising combining hydrochloric acid and an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone in a solvent to form a solution; and spray drying the solution to generate oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising combining hydrochloric acid and an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone in a solvent to form a solution; and lyophilizing the solution to generate oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm.

In certain embodiments, the invention is directed to a process for preparing an oxycodone hydrochloride composition comprising combining hydrochloric acid and an oxycodone base composition in a solvent to form a solution; and lyophilizing the solution to generate oxycodone hydrochloride. The term â€œbulkâ€ means an amount of material of at least 1 kg. In certain embodiments, the amount can be from about 10 kg to about 1000 kg or from about 10 kg to about 500 kg. In certain embodiments, the amount is in an amount of from about 20 kg to about 100 kg; about 20 kg or about 50 kg. Bulk oxycodone hydrochloride composition can be packaged, e.g., in a pharmaceutically acceptable package such as corrugated box containers (made of, e.g., plastic and/or paper); in drums (made of, e.g., a metal or metal composite material); or in bags of woven fabric generally referred to as flexible intermediate bulk containers (FIBCs). Each of these approaches use various configurations of liners, typically made of polyethylene or polypropylene, that fit within the corrugated box, drum, or within the FIBC for preventing contamination of the product being shipped. Preferably, these packaging approaches use containers configured to be supported by and carried on pallets.

The term â€œppmâ€ as used herein means â€œparts per millionâ€ . As used to refer to 14-hydroxycodeinone, â€œppmâ€ means parts per million of 14-hydroxycodeinone in a particular sample.

The term 8,14-dihydroxy-7,8-dihydrocodeinone includes either 8Î±,14-dihydroxy-7,8-dihydrocodeinone; or 8Î²,14-dihydroxy-7,8-dihydrocodeinone or can include a mixture of both compounds.

The oxycodone hydrochloride preparation can be, e.g., an oxycodone active pharmaceutical ingredient (API), such as oxycodone hydrochloride U.S.P., uncombined or combined with one or more other ingredients. For example, the oxycodone preparation can be a final pharmaceutical dosage form, or an intermediate preparation for a final dosage form, that can be tested for the presence of 14-hydroxycodeinone and/or codeinone, e.g., for quality assurance purposes. Preferably, the oxycodone hydrochloride preparation is oxycodone hydrochloride API and contains at least 95% oxycodone hydrochloride, at least 98% oxycodone hydrochloride, at least 99% oxycodone hydrochloride, or at least 99.9% oxycodone hydrochloride.

The method of detecting the presence of 14-hydroxycodeinone in an oxycodone preparation can be performed in accordance with commonly assigned U.S. Provisional Application Ser. No. 60/557,502, entitled â€œMethods For Detecting 14-Hydroxycodeinoneâ€ filed Mar. 29, 2004 and in accordance with U.S. Provisional Application entitled â€œMethods For Detecting 14-Hydroxycodeinoneâ€ filed Jan. 31, 2005.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a schematic of a reaction of thebaine to oxycodone hydrochloride, including the oxidation of thebaine to 14-hydroxycodeinone and the 8,14-dihydroxy-7,8-dihydrocodeinone impurity.

FIG. 2

is a schematic of the dehydration of 8,14-dihydroxy-7,8-dihydrocodeinone to 14-hydroxycodeinone.

FIG. 3

depicts a separation of the system suitability testing solution of Example 4.

FIG. 4

depicts a HPLC chromatogram for the Working 100 PPM 14OHC Standard Solution of Example 4.

FIG. 5

depicts typical HPLC chromatogram for the Oxycodone API Sample Solution of Example 4.

DETAILED DESCRIPTION

In certain embodiments, the invention is directed to a process for reducing the amount of 14-hydroxycodeinone in an oxycodone hydrochloride composition (e.g., oxycodone hydrochloride API), and to the resultant oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm recovered from that process. In certain embodiments, the present invention is directed to a process for reducing the amount of 14-hydroxycodeinone in an oxycodone hydrochloride composition comprising reacting the oxycodone hydrochloride composition with a catalytically effective amount of a transition metal compound and a gas comprising hydrogen, at a temperature and for a period of time sufficient to reduce the content of 14-hydroxycodeinone to a level wherein the resultant oxycodone hydrochloride composition comprises 14-hydroxycodeinone in an amount less than 25 ppm, less than about 15 ppm; less than about 10 ppm, or less than about 5 ppm.

The process of the present invention also may result in the reduction of other alpha, beta, unsaturated ketones in oxycodone compositions, in addition to 14-hydroxycodeinone such as, e.g., codeinone.

In accordance with certain embodiments of the present invention, an oxycodone hydrochloride composition (e.g., oxycodone hydrochloride API), and a solvent, are fed into a reaction apparatus. The composition is then hydrogenated under adequate conditions for a sufficient period; the catalyst is removed from the solvent; and the oxycodone hydrochloride composition having a 14-hydroxycodeinone level of less than 25 ppm is isolated and removed, e.g., by crystallization and filtration.

Hydrogenation of the 14-hydroxycodeinone in the processes of the present invention can be accomplished by using, e.g., pressurized-catalytic hydrogenation or catalytic transfer hydrogenation in an appropriate acid, e.g., acetic acid. A particular hydrogenation reaction employs hydrogen gas or NaHPO₂along with a palladium-carbon catalyst. In certain embodiments, a hydrogen donor for use in the hydrogenation of the 14-hydroxycodeinone can be selected from hydrogen, primary and secondary alcohols, primary and secondary amines, carboxylic acids and their esters and amine salts, readily dehydrogenatable hydrocarbons (e.g., lower alkyl-substituted aromatic hydrocarbons such as ethylbenzene, diethylbenzene, isopropylbenzene, diisopropylbenzene, o-ethyltoluene, m-ethyltoluene, p-ethyltoluene, o-isopropyltoluene, m-isopropyltoluene, p-isopropyltoluene, ethylnaphthalene, propylnapththalene, isopropylnaphthalene, and diethylnaphthalene; paraffins such as ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, and branched chain isomers thereof; cycloparaffins such as cyclobutane, cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, and ethylcyclopentane; olefins such as ethylene, propylene, 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, and branched chain derivatives thereof), clean reducing agents (e.g., polymer-supported organotin hydrides, and any suitable combination thereof. In certain embodiments, the hydrogenation can be performed as disclosed in U.S. Provisional Application No. 60/477,968, filed Jun. 12, 2003, entitled â€œHydrogenation of Opioids Without Hydrogen Gas Feed.â€

In certain embodiments, the hydrogenation is carried out at a pressure from about 5 PSIG to about 200 PSIG, or from about 40 PSIG to about 60 PSIG. In certain embodiments, the hydrogenation is carried out at a temperature of from about 20Â° C. to about 100Â° C., or from about 40Â° C. to about 85Â° C.

In certain embodiments, the hydrogenation is carried out at a pH of less than 5, less than 3, or less than 1, e.g., about 0.5.

In certain embodiments of the present invention, the 14-hydroxycodeinone is converted to oxycodone by hydrogenation utilizing diphenylsilane and Pd(Ph₃P)/ZnCl₂and sodium hypophosphite in conjunction with a Pd/C catalyst in aqueous organic acid; or Pd/C catalytic transfer hydrogenation.

The total reaction time of the hydrogenation reaction is for a duration sufficient to reduce the content of the 14-hydroxycodeinone to a level that is less than 25 ppm, less than about 15 ppm, less than about 10 ppm, or less than about 5 ppm. The actual reaction time can vary depending upon the temperature and efficiency of the hydrogenation system. Depending on the hydrogenation conditions (e.g., temperature and pressure), the total reaction time to achieve the desired reduction in 14-hydroxycodeinone can be, e.g., from about 10 minutes to about 36 hours. The hydrogenation of the 14-hydroxycodeinone can be carried out in the presence of a noble metal catalyst. In certain embodiments, suitable catalysts can be selected from Raney cobalt, Raney nickel, palladium on carbon, platinum on carbon, palladium on alumina, platinum oxide, ruthenium on alumina, rhodium on alumina, or rhodium on carbon, among others. One particular catalyst for this reduction is 5% palladium on carbon. The quantity of palladium on carbon catalyst can be from about 0.05% w/w to about 50% w/w, or from about 0.5% w/w to about 5%, in relation to the treated composition.

The reaction may be carried out in a solvent such as water; an alcohol (such as, e.g., isopropanol, methanol or ethanol); tetrahydrofuran; an aromatic hydrocarbon (such as benzene); an ether (such as dioxane); an ester of a lower alkanoic acid (such as methyl acetate or ethyl acetate); an amide (such as, e.g., dimethylformamide, diethylformamide, dimethylacetomide, or other N-alkyl substituted lower fatty acid amides); N-methylpyrrolidone; formylmorpholine; Î²-methoxypropionitrile; a carboxylic acid (such as formic, acetic, propionic acid or other lower alkanoic acid) or an appropriate mixture of any two or more of the aforementioned solvents. One particular co-solvent combination is isopropanol/water.

In certain embodiments, the solvent is typically mixed with the 14-hydroxycodeinone-containing composition (e.g., an oxycodone composition) prior to hydrogenation.

In certain embodiments, the invention is directed to the conversion of an oxycodone free base composition (with an 8,14-dihydroxy-7,8-dihydrocodeinone component) to oxycodone hydrochloride. During salt formation reactions known in the art, the 8,14-dihydroxy-7,8-dihydrocodeinone component is converted to 14-hydroxycodeinone by acid-catalyzed dehydration. Thus, 14-hydroxycodeinone is increased in the final product. By virtue of the present invention, this can be reduced by overloading the amount of hydrochloric acid in the salt formation to promote the reaction of 8,14-dihydroxy-7,8-dihydrocodeinone to 14-hydroxycodeinone and providing reducing conditions sufficient for the 14-hydroxycodeinone to be readily converted to oxycodone. In such an embodiment, the amount of hydrochloric acid is an amount of greater than 1 molar equivalent as compared to the oxycodone free base. In certain embodiments, the molar equivalent amount of hydrochloric acid can be greater than about 1.2 molar equivalents or greater than about 1.4 molar equivalents. In certain embodiments, the amount of hydrochloric acid can be about 1.5 molar equivalents. The reducing conditions sufficient to drive the 14-hydroxycodeinone to oxycodone can be provided, e.g., by a catalyst with a hydrogen donor.

Further, during salt formation, the rate of dehydration of 8,14-dihydroxy-7,8-dihydrocodeinone to 14-hydroxycodeinone is reduced as the pH of the solution increases. Therefore, in certain embodiments, the pH of the solution can be adjusted to a pH of from about 1.5 to about 2.5, preferably to about 1.8, (e.g., from a pH of less than 1) with a suitable basic agent, e.g., sodium hydroxide. This further minimizes the formation of 14-hydroxycodeinone from 8,14-dihydroxy-7,8-dihydrocodeinone during crystallization. Preferably, the pH adjustment is performed after the hydrogenation step and prior to removal of catalyst and isolation of the oxycodone having a 14-hydroxycodeinone level of less than 25 ppm.

In certain embodiments it may be necessary to perform the process of the present invention, or one or more relevant steps in the process of the present invention, more than once in order to reduce the amount of 14-hydroxycodeinone to a desired level, e.g., less than about 10 ppm, or less than about 5 ppm.

In certain embodiments of the present invention, oxycodone hydrochloride compositions can be prepared by certain alternative processes. Such alternative processes preferably result in an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm. One such alternative process is directed to a process for preparing an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone comprising oxidizing a thebaine composition to form 14-hydroxycodeinone composition, the oxidizing being performed at a suitable pH to minimize or eliminate the production of 8,14-dihydroxy-7,8-dihydrocodeinone in the 14-hydroxycodeinone composition; hydrogenating the 14-hydroxycodeinone composition to form an oxycodone base composition; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone.

Another alternative process is directed to a process for preparing 14-hydroxycodeinone comprising oxidizing a thebaine composition to form a 14-hydroxycodeinone composition, the oxidizing being performed at a suitable pH to minimize or eliminate the production of 8,14-dihydroxy-7,8-dihydrocodeinone in the 14-hydroxycodeinone composition.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition comprising reacting an oxycodone base composition with an acid having a higher pH than hydrochloric acid to form a corresponding acid addition salt of oxycodone, and converting the acid addition salt of oxycodone to oxycodone hydrochloride. In such an embodiment, the acid may be selected from the group consisting of tartaric acid, oxalic acid, fumaric acid, phosphoric acid, sulfuric acid and mixtures thereof.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising contacting an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone with a substance that preferentially removes the 8,14-dihydroxy-7,8-dihydrocodeinone as compared to the oxycodone base; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone. In preferred embodiments the contacting substance can be a gel. In further embodiments, the contacting can comprise passing a solution comprising the oxycodone base composition through the substance or can comprise forming a slurry with the oxycodone base composition and the gel.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising subjecting an oxycodone base composition having an amount of 8,14-dihydroxy-7,8-dihydrocodeinone to chromatographic separation to preferentially remove the 8,14-dihydroxy-7,8-dihydrocodeinone as compared to the oxycodone base; and converting the oxycodone base composition to an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone. In preferred embodiments, the chromatographic separation is a simulated moving bed.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising contacting an oxycodone hydrochloride composition having an amount of 14-hydroxycodeinone with a substance that preferentially removes the 14-hydroxycodeinone as compared to the oxycodone hydrochloride; and recovering an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone. In preferred embodiments the contacting substance can be a gel. In further embodiments, the contacting can comprise passing a solution comprising the oxycodone hydrochloride composition through the substance or can comprise forming a slurry with the oxycodone hydrochloride composition and the gel.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition having a 14-hydroxycodeinone level in an amount of less than 25 ppm comprising subjecting an oxycodone hydrochloride composition having an amount of 14-hydroxycodeinone to chromatographic separation to preferentially remove the 14-hydroxycodeinone as compared to the oxycodone hydrochloride; and recovering an oxycodone hydrochloride composition having less than 25 ppm 14-hydroxycodeinone. In preferred embodiments, the chromatographic separation is a simulated moving bed.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition comprising reacting in a suitable solvent an oxycodone base composition with boronated polystyrene resin; and converting the oxycodone base composition to an oxycodone hydrochloride composition. Preferably the reacting is performed at a temperature below about 20 degrees C.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition comprising combining hydrochloric acid and an oxycodone base composition in a solvent to form a solution; and spray drying the solution to generate oxycodone hydrochloride.

Another alternative process is directed to a process for preparing an oxycodone hydrochloride composition comprising combining hydrochloric acid and an oxycodone base composition in a solvent to form a solution; and lyophilizing the solution to generate oxycodone hydrochloride.

Further Embodiments

The oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm can be incorporated into pharmaceutical dosage forms, e.g., by admixtures of the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm with conventional excipients, i.e., pharmaceutically acceptable organic or inorganic carrier substances. For oral formulations, the dosage forms can provide a sustained release of the active. Suitable pharmaceutically acceptable carriers include but are not limited to, alcohols, gum arabic, vegetable oils, benzyl alcohols, polyethylene glycols, gelate, carbohydrates such as lactose, amylose or starch, magnesium stearate, talc, silicic acid, viscous paraffin, perfume oil, fatty acid monoglycerides and diglycerides, pentaerythritol fatty acid esters, hydroxymethylcellulose, polyvinylpyrrolidone, etc. The pharmaceutical preparations can be sterilized and if desired mixed with auxiliary agents, e.g., lubricants, disintegrants, preservatives, stabilizers, wetting agents, emulsifiers, salts for influencing osmotic pressure buffers, coloring, flavoring and/or aromatic substances and the like. The compositions intended for oral use may be prepared according to any method known in the art and such compositions may contain one or more agents selected from the group consisting of inert, non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. Such excipients include, for example an inert diluent such as lactose; granulating and disintegrating agents such as cornstarch; binding agents such as starch; and lubricating agents such as magnesium stearate. The tablets may be uncoated or they may be coated by known techniques for elegance or to delay release of the active ingredients. Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert diluent. The oral dosage forms of the present invention may be in the form of tablets (sustained release and/or immediate release), troches, lozenges, powders or granules, hard or soft capsules, microparticles (e.g., microcapsules, microspheres and the like), buccal tablets, suppositories, solutions, suspensions, etc.

In certain embodiments, the present invention provides for a method of treating pain by administering to a human patient the dosage forms described herein.

When the dosage form is oral, the dosage form of the present invention contains from about 10 mg to about 320 mg of oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm. Particularly preferred dosages for twice daily dosing are about 5 mg, about 10 mg, about 15 mg, about 20 mg, about 30 mg, about 40 mg, about 50 mg, about 60 mg, about 80 mg, about 100 mg, or about 160 mg. Particularly preferred dosages for once daily dosing are about 10 mg, about 20 mg, about 30 mg, about 40 mg, about 60 mg, about 80 mg, about 100 mg, about 120 mg, about 160 mg, or about 320 mg. The oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm can also be formulated with suitable pharmaceutically acceptable excipients to provide a sustained release of the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm. Such formulations can be prepared in accordance with U.S. Pat. Nos. 5,266,331; 5,508,042; 5,549,912; and 5,656,295.

The oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm can be formulated as a sustained release oral formulation in any suitable tablet, coated tablet or multiparticulate formulation known to those skilled in the art. The sustained release dosage form may include a sustained release material which is incorporated into a matrix along with the oxycodone or salt thereof.

The sustained release dosage form may optionally comprise particles containing oxycodone having a 14-hydroxycodeinone level of less than 25 ppm. In certain embodiments, the particles have a diameter from about 0.1 mm to about 2.5 mm, preferably from about 0.5 mm to about 2 mm. Preferably, the particles are film coated with a material that permits release of the active at a sustained rate in an aqueous medium. The film coat is chosen so as to achieve, in combination with the other stated properties, desired release properties. The sustained release coating formulations of the present invention should preferably be capable of producing a strong, continuous film that is smooth and elegant, capable of supporting pigments and other coating additives, non-toxic, inert, and tack-free.

Coated Beads

In certain embodiments of the present invention a hydrophobic material is used to coat inert pharmaceutical beads such as nu pariel 18/20 beads, and a plurality of the resultant solid sustained release beads may thereafter be placed in a gelatin capsule in an amount sufficient to provide an effective sustained release dose when ingested and contacted by an environmental fluid, e.g., gastric fluid or dissolution media.

The sustained release bead formulations of the present invention slowly release the active of the present invention, e.g., when ingested and exposed to gastric fluids, and then to intestinal fluids. The sustained release profile of the formulations of the invention can be altered, for example, by varying the amount of overcoating with the hydrophobic material, altering the manner in which a plasticizer is added to the hydrophobic material, by varying the amount of plasticizer relative to hydrophobic material, by the inclusion of additional ingredients or excipients, by altering the method of manufacture, etc. The dissolution profile of the ultimate product may also be modified, for example, by increasing or decreasing the thickness of the retardant coating.

Spheroids or beads coated with the agent(s) of the present are prepared, e.g., by dissolving the agent(s) in water and then spraying the solution onto a substrate, for example, nu pariel 18/20 beads, using a Wuster insert. Optionally, additional ingredients are also added prior to coating the beads in order to assist the binding of the active to the beads, and/or to color the solution, etc. For example, a product which includes hydroxypropylmethylcellulose, etc. with or without colorant (e.g., OpadryÂ®, commercially available from Colorcon, Inc.) may be added to the solution and the solution mixed (e.g., for about 1 hour) prior to application of the same onto the beads. The resultant coated substrate, in this example beads, may then be optionally overcoated with a barrier agent, to separate the active(s) from the hydrophobic sustained release coating. An example of a suitable barrier agent is one which comprises hydroxypropylmethylcellulose. However, any film-former known in the art may be used. It is preferred that the barrier agent does not affect the dissolution rate of the final product.

The beads may then be overcoated with an aqueous dispersion of the hydrophobic material. The aqueous dispersion of hydrophobic material preferably further includes an effective amount of plasticizer, e.g. triethyl citrate. Pre-formulated aqueous dispersions of ethylcellulose, such as AquacoatÂ® or SureleaseÂ®, may be used. If SureleaseÂ® is used, it is not necessary to separately add a plasticizer. Alternatively, pre-formulated aqueous dispersions of acrylic polymers such as EudragitÂ® can be used.

The coating solutions of the present invention preferably contain, in addition to the film-former, plasticizer, and solvent system (i.e., water), a colorant to provide elegance and product distinction. Color may be added to the solution of the therapeutically active agent instead, or in addition to the aqueous dispersion of hydrophobic material. For example, color may be added to AquacoatÂ® via the use of alcohol or propylene glycol based color dispersions, milled aluminum lakes and opacifiers such as titanium dioxide by adding color with shear to water soluble polymer solution and then using low shear to the plasticized AquacoatÂ®. Alternatively, any suitable method of providing color to the formulations of the present invention may be used. Suitable ingredients for providing color to the formulation when an aqueous dispersion of an acrylic polymer is used include titanium dioxide and color pigments, such as iron oxide pigments. The incorporation of pigments, may, however, increase the retard effect of the coating.

Plasticized hydrophobic material may be applied onto the substrate comprising the agent(s) by spraying using any suitable spray equipment known in the art. In a preferred method, a Wurster fluidized-bed system is used in which an air jet, injected from underneath, fluidizes the core material and effects drying while the acrylic polymer coating is sprayed on. A sufficient amount of the hydrophobic material to obtain a predetermined sustained release of the agent(s) when the coated substrate is exposed to aqueous solutions, e.g. gastric fluid, may be applied. After coating with the hydrophobic material, a further overcoat of a film-former, such as OpadryÂ®, is optionally applied to the beads. This overcoat is provided, if at all, in order to substantially reduce agglomeration of the beads.

The release of the agent(s) from the sustained release formulation of the present invention can be further influenced, i.e., adjusted to a desired rate, by the addition of one or more release-modifying agents, or by providing one or more passageways through the coating. The ratio of hydrophobic material to water soluble material is determined by, among other factors, the release rate required and the solubility characteristics of the materials selected.

The release-modifying agents which function as pore-formers may be organic or inorganic, and include materials that can be dissolved, extracted or leached from the coating in an environment of use. The pore-formers may comprise one or more hydrophilic materials such as hydroxypropylmethylcellulose.

The sustained release coatings of the present invention can also include erosion-promoting agents such as starch and gums.

The sustained release coatings of the present invention can also include materials useful for making microporous lamina in the environment of use, such as polycarbonates comprised of linear polyesters of carbonic acid in which carbonate groups reoccur in the polymer chain.

The release-modifying agent may also comprise a semi-permeable polymer.

In certain preferred, embodiments, the release-modifying agent is selected from hydroxypropylmethylcellulose, lactose, metal stearates, and mixtures of any of the foregoing.

The sustained release coatings of the present invention may also include an exit means comprising at least one passageway, orifice, or the like. The passageway may be formed by such methods as those disclosed in U.S. Pat. Nos. 3,845,770; 3,916,8989; 4,063,064; and 4,088,864.

Matrix Formulations

In other embodiments of the present invention, the sustained release formulation is achieved via a matrix optionally having a sustained release coating as set forth herein. The materials suitable for inclusion in a sustained release matrix may depend on the method used to form the matrix.

For example, a matrix in addition to the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm may include:

Hydrophilic and/or hydrophobic materials, such as gums, cellulose ethers, acrylic resins, protein derived materials; the list is not meant to be exclusive, and any pharmaceutically acceptable hydrophobic material or hydrophilic material which is capable of imparting sustained release of the agent(s) and which melts (or softens to the extent necessary to be extruded) may be used in accordance with the present invention.

Digestible, long chain (C₈-C₅₀, especially C₁₂-C₄₀), substituted or unsubstituted hydrocarbons, such as fatty acids, fatty alcohols, glyceryl esters of fatty acids, mineral and vegetable oils and waxes, and stearyl alcohol; and polyalkylene glycols.

Of these polymers, acrylic polymers, especially EudragitÂ® RSPOâ€”the cellulose ethers, especially hydroxyalkylcelluloses and carboxyalkylcelluloses, are preferred. The oral dosage form may contain between 1% and 80% (by weight) of at least one hydrophilic or hydrophobic material.

When the hydrophobic material is a hydrocarbon, the hydrocarbon preferably has a melting point of between 25Â° and 90Â° C. Of the long chain hydrocarbon materials, fatty (aliphatic) alcohols are preferred. The oral dosage form may contain up to 60% (by weight) of at least one digestible, long chain hydrocarbon.

Preferably, the oral dosage form contains up to 60% (by weight) of at least one polyalkylene glycol.

The hydrophobic material is preferably selected from the group consisting of alkylcelluloses, acrylic and methacrylic acid polymers and copolymers, shellac, zein, hydrogenated castor oil, hydrogenated vegetable oil, or mixtures thereof. In certain preferred embodiments of the present invention, the hydrophobic material is a pharmaceutically acceptable acrylic polymer, including but not limited to acrylic acid and methacrylic acid copolymers, methyl methacrylate, methyl methacrylate copolymers, ethoxyethyl methacrylates, cyanoethyl methacrylate, aminoalkyl methacrylate copolymer, poly(acrylic acid), poly(methacrylic acid), methacrylic acid alkylamine copolymer, poly(methyl methacrylate), poly(methacrylic acid)(anhydride), polymethacrylate, polyacrylamide, poly(methacrylic acid anhydride), and glycidyl methacrylate copolymers. In other embodiments, the hydrophobic material is selected from materials such as hydroxyalkylcelluloses such as hydroxypropylmethylcellulose and mixtures of the foregoing.

Preferred hydrophobic materials are water-insoluble with more or less pronounced hydrophilic and/or hydrophobic trends. Preferably, the hydrophobic materials useful in the invention have a melting point from about 2530Â° to about 200Â° C., preferably from about 45Â° C. to about 90Â° C. Specifically, the hydrophobic material may comprise natural or synthetic waxes, fatty alcohols (such as lauryl, myristyl, stearyl, cetyl or preferably cetostearyl alcohol), fatty acids, including but not limited to fatty acid esters, fatty acid glycerides (mono-, di-, and tri-glycerides), hydrogenated fats, hydrocarbons, normal waxes, stearic aid, stearyl alcohol and hydrophobic and hydrophilic materials having hydrocarbon backbones. Suitable waxes include, for example, beeswax, glycowax, castor wax and camauba wax. For purposes of the present invention, a wax-like substance is defined as any material which is normally solid at room temperature and has a melting point of from about 25Â° to about 100Â° C.

Suitable hydrophobic materials which may be used in accordance with the present invention include digestible, long chain (C₈-C₅₀, especially C₁₂-C₄₀), substituted or unsubstituted hydrocarbons, such as fatty acids, fatty alcohols, glyceryl esters of fatty acids, mineral and vegetable oils and natural and synthetic waxes. Hydrocarbons having a melting point of between 25Â° and 90Â° C. are preferred. Of the long chain hydrocarbon materials, fatty (aliphatic) alcohols are preferred in certain embodiments. The oral dosage form may contain up to 60% (by weight) of at least one digestible, long chain hydrocarbon.

Preferably, a combination of two or more hydrophobic materials are included in the matrix formulations. If an additional hydrophobic material is included, it is preferably selected from natural and synthetic waxes, fatty acids, fatty alcohols, and mixtures of the same. Examples include beeswax, camauba wax, stearic acid and stearyl alcohol. This list is not meant to be exclusive.

One particular suitable matrix comprises at least one water soluble hydroxyalkyl cellulose, at least one C₁₂-C₃₆, preferably C₁₄-C₂₂, aliphatic alcohol and, optionally, at least one polyalkylene glycol. The at least one hydroxyalkyl cellulose is preferably a hydroxy (C₁to C₆) alkyl cellulose, such as hydroxypropylcellulose, hydroxypropylmethylcellulose and, especially, hydroxyethylcellulose. The amount of the at least one hydroxyalkyl cellulose in the present oral dosage form will be determined, inter alia, by the precise rate of oxycodone hydrochloride release required. The at least one aliphatic alcohol may be, for example, lauryl alcohol, myristyl alcohol or stearyl alcohol. In particularly preferred embodiments of the present oral dosage form, however, the at least one aliphatic alcohol is cetyl alcohol or cetostearyl alcohol. The amount of the at least one aliphatic alcohol in the present oral dosage form will be determined, as above, by the precise rate of opioidoxycodone release required. It will also depend on whether at least one polyalkylene glycol is present in or absent from the oral dosage form. In the absence of at least one polyalkylene glycol, the oral dosage form preferably contains between 20% and 50% (by wt) of the at least one aliphatic alcohol. When at least one polyalkylene glycol is present in the oral dosage form, then the combined weight of the at least one aliphatic alcohol and the at least one polyalkylene glycol preferably constitutes between 20% and 50% (by wt) of the total dosage.

In one embodiment, the ratio of, e.g., the at least one hydroxyalkyl cellulose or acrylic resin to the at least one aliphatic alcohol/polyalkylene glycol determines, to a (w/w) of the at least one hydroxyalkyl cellulose to the at least one aliphatic alcohol/polyalkylene glycol of between 1:2 and 1:4 is preferred, with a ratio of between 1:3 and 1:4 being particularly preferred.

The at least one polyalkylene glycol may be, for example, polypropylene glycol or, which is preferred, polyethylene glycol. The number average molecular weight of the at least one polyalkylene glycol is preferred between 1,000 and 15,000 especially between 1,500 and 12,000.

Another suitable sustained release matrix would comprise an alkylcellulose (especially ethyl cellulose), a C₁₂to C₃₆aliphatic alcohol and, optionally, a polyalkylene glycol.

In another preferred embodiment, the matrix includes a pharmaceutically acceptable combination of at least two hydrophobic materials.

In addition to the above ingredients, a sustained release matrix may also contain suitable quantities of other materials, e.g. diluents, lubricants, binders, granulating aids, colorants, flavorants and glidants that are conventional in the pharmaceutical art.

Matrixâ€”Particulates

In order to facilitate the preparation of a solid, sustained release, oral dosage form according to this invention, any method of preparing a matrix formulation known to those skilled in the art may be used. For example incorporation in the matrix may be effected, for example, by (a) forming granules comprising at least one water soluble hydroxyalkyl cellulose, and the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm; (b) mixing the hydroxyalkyl cellulose containing granules with at least one C₁₂-C₃₆aliphatic alcohol; and (c) optionally, compressing and shaping the granules. Preferably, the granules are formed by wet granulating the hydroxalkyl cellulose granules with water.

In yet other alternative embodiments, a spheronizing agent, together with the active can be spheronized to form spheroids. Microcrystalline cellulose is a preferred spheronizing agent. A suitable microcrystalline cellulose is, for example, the material sold as Avicel PH 101 (Trade Mark, FMC Corporation). In such embodiments, in addition to the active ingredient and spheronizing agent, the spheroids may also contain a binder. Suitable binders, such as low viscosity, water soluble polymers, will be well known to those skilled in the pharmaceutical art. However, water soluble hydroxy lower alkyl cellulose, such as hydroxypropylcellulose, are preferred. Additionally (or alternatively) the spheroids may contain a water insoluble polymer, especially an acrylic polymer, an acrylic copolymer, such as a methacrylic acid-ethyl acrylate copolymer, or ethyl cellulose. In such embodiments, the sustained release coating will generally include a hydrophobic material such as (a) a wax, either alone or in admixture with a fatty alcohol; or (b) shellac or zein.

Melt Extrusion Matrix

Sustained release matrices can also be prepared via melt-granulation or melt-extrusion techniques. Generally, melt-granulation techniques involve melting a normally solid hydrophobic material, e.g. a wax, and incorporating a powdered drug therein. To obtain a sustained release dosage form, it may be necessary to incorporate an additional hydrophobic substance, e.g. ethylcellulose or a water-insoluble acrylic polymer, into the molten wax hydrophobic material. Examples of sustained release formulations prepared via melt-granulation techniques are found in U.S. Pat. No. 4,861,598.

The additional hydrophobic material may comprise one or more water-insoluble wax-like thermoplastic substances possibly mixed with one or more wax-like thermoplastic substances being less hydrophobic than said one or more water-insoluble wax-like substances. In order to achieve constant release, the individual wax-like substances in the formulation should be substantially non-degradable and insoluble in gastrointestinal fluids during the initial release phases. Useful water-insoluble wax-like substances may be those with a water-solubility that is lower than about 1:5,000 (w/w).

In addition to the above ingredients, a sustained release matrix may also contain suitable quantities of other materials, e.g., diluents, lubricants, binders, granulating aids, colorants, flavorants and glidants that are conventional in the pharmaceutical art. The quantities of these additional materials will be sufficient to provide the desired effect to the desired formulation.

In addition to the above ingredients, a sustained release matrix incorporating melt-extruded multiparticulates may also contain suitable quantities of other materials, e.g. diluents, lubricants, binders, granulating aids, colorants, flavorants and glidants that are conventional in the pharmaceutical art in amounts up to about 50% by weight of the particulate if desired.

Specific examples of pharmaceutically acceptable carriers and excipients that may be used to formulate oral dosage forms are described in the Handbook of Pharmaceutical Excipients, American Pharmaceutical Association (1986).

Melt Extrusion Multiparticulates

The preparation of a suitable melt-extruded matrix according to the present invention may, for example, include the steps of blending the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm together with at least one hydrophobic material and preferably the additional hydrophobic material to obtain a homogeneous mixture. The homogeneous mixture is then heated to a temperature sufficient to at least soften the mixture sufficiently to extrude the same. The resulting homogeneous mixture is then extruded to form strands. The extrudate is preferably cooled and cut into multiparticulates by any means known in the art. The strands are cooled and cut into multiparticulates. The multiparticulates are then divided into unit doses. The extrudate preferably has a diameter of from about 0.1 to about 5 mm and provides sustained release of the therapeutically active agent for a time period of from about 8 to about 24 hours.

An optional process for preparing the melt extrusions of the present invention includes directly metering into an extruder a hydrophobic material, the oxycodone hydrochloride having a 14-hydroxycodeinone level of less than 25 ppm, and an optional binder; heating the homogenous mixture; extruding the homogenous mixture to thereby form strands; cooling the strands containing the homogeneous mixture; cutting the strands into particles having a size from about 0.1 mm to about 12 mm; and dividing said particles into unit doses. In this aspect of the invention, a relatively continuous manufacturing procedure is realized.

The diameter of the extruder aperture or exit port can also be adjusted to vary the thickness of the extruded strands. Furthermore, the exit part of the extruder need not be round; it can be oblong, rectangular, etc. The exiting strands can be reduced to particles using a hot wire cutter, guillotine, etc.

The melt extruded multiparticulate system can be, for example, in the form of granules, spheroids or pellets depending upon the extruder exit orifice. For purposes of the present invention, the terms â€œmelt-extruded multiparticulate(s)â€ and â€œmelt-extruded multiparticulate system(s)â€ and â€œmelt-extruded particlesâ€ shall refer to a plurality of units, preferably within a range of similar size and/or shape and containing one or more active agents and one or more excipients, preferably including a hydrophobic material as described herein. In this regard, the melt-extruded multiparticulates will be of a range of from about 0.1 to about 12 mm in length and have a diameter of from about 0.1 to about 5 mm. In addition, it is to be understood that the melt-extruded multiparticulates can be any geometrical shape within this size range. Alternatively, the extrudate may simply be cut into desired lengths and divided into unit doses of the therapeutically active agent without the need of a spheronization step.

In one preferred embodiment, oral dosage forms are prepared to include an effective amount of melt-extruded multiparticulates within a capsule. For example, a plurality of the melt-extruded multiparticulates may be placed in a gelatin capsule in an amount sufficient to provide an effective sustained release dose when ingested and contacted by gastric fluid.

In another preferred embodiment, a suitable amount of the multiparticulate extrudate is compressed into an oral tablet using conventional tableting equipment using standard techniques. Techniques and compositions for making tablets (compressed and molded), capsules (hard and soft gelatin) and pills are also described in Remington's Pharmaceutical Sciences, (Arthur Osol, editor), 1553-1593 (1980).

In yet another preferred embodiment, the extrudate can be shaped into tablets as set forth in