MODIFIED RELEASE GEMFIBROZIL COMPOSITION

Abstract: A disintegratable formulation of gemfibrozil providing both immediate and sustained release and com­ prises a tablet compressed from a mixture of a first and second granulation, and a disintegration excipient operable to effect partial or complete disintegration in the stomach. The first granulation comprises finely divided particles of pure gemfibrozil granulated with at least one cellulose derivative and the second granu­ lation comprises finely divided particles of pure gem­ fibrozil granulated with a pharmaceutically acceptable water soluble or insoluble polymer which are then uni­ formly coated with a pharmaceutically acceptable (meth)acrylate copolymer prior to admixture with the first granulation. The first and second granulations are present in the final composition in a ratio of from about 10:1 to about 1:10.

Description: The present invention relates to modified release gemfibrozil formulations. Background Gemfibrozil, or 5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid, is a widely used antihyperlipoproteinemic agent. While apparently absorbed throughout the gastrointestinal tract, maximum absorption appears to occur in the upper gastrointestinal tract and this is true notwithstanding the poor solubility of the drug at acidic pH. Prior attempts at developing sustained release formulations, as for example reservoir systems, have not met with a great deal of success, producing either inadequate bioavailability or unacceptable release profiles. Paradoxically, it appears the achievement of a sustained release formulation requires disintegration or erosion in the stomach. British Application 2,179,254 discloses compositions of analgesic propionic acid derivatives (such as ibuprofen) coated with a methacrylic-acrylic copolymer, then with a methacrylic ester copolymer, and finally with a mixture of polysorbate 80 and hydroxypropyl methylcellulose. EPO-A 190 255 discloses sustained release compositions of polyethylene glycol and an amphiphilic compound. French Application 2,554,717 discloses sustained release compositions which employs as the matrix a vinylpyrrolidone-vinyl acetate copolymer and an acrylic polymer cross-linked with polyallyl sucrose. (See also Belgian application 901007.) U.S. Patent No. 4,132,753 discloses controlled release granules in which the powdered medicament is heated so as to sink into a finely divided wax material. U.S. Patent No. 4,195,084 discloses a liquid suspension of finely ground tall oil sitosterols for use in reducing hypercholesteraemia. U.S. Patent No. 4,263,272 discloses three component formulations of bile acids which release gradually or in two stages. U.S. Patent No. 4,291,016 discloses pharmaceutical compositions having a matrix core coated with hydroxypropyl methyl cellulose. U.S. Patent No. 4,533,562 discloses tablets coated with a film-forming polymer such as hydroxypropyl methylcellulose and a liquid plasticizer such as polyethylene glycol. U.S. Patent No. 4,661,162 discloses an enteric soluble composition containing a mixture of an enteric-soluble polymer such as (m)ethyl acrylate/methacrylate copolymers and a polyanionic polymer such as alginic acid and its salts. Detailed Description The present invention relates to a disintegratable formulation of gemfibrozil providing both immediate and sustained release. Specifically the invention comprises a tablet compressed from (i) a first granulation as hereinafter described, (ii) a second granulation as hereinafter described, and (iii) a disintegration excipient operable to effect partial or complete disintegration of the tablet in the stomach. The first granulation comprises finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, granulated with at least one cellulose derivative, sugar, or polyvinyl pyrrolidone. Suitable cellulose derivatives include microcrystalline cellulose, water soluble hydroxyalkylcelluloses such as hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose. Mixtures of the cellulose derivatives are particularly preferred. The second granulation comprising finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, granulated with a pharmaceutically acceptable water soluble or insoluble polymer with the granulation then being uniformly coated with a pharmaceutically acceptable sustaining material comprising a (meth)acrylate ester copolymer and/or ethyl cellulose and cellulose acetate prior to admixture with said first granulation. The sustaining polymeric component utilized in the second granulation contains preferably at least one water insoluble (meth)acrylate ester copolymer. The use of "meth" as a prefix in parenthesis indicates that the polymer molecule is derived from one or both of acrylic and methacrylic species. Thus, the copolymer may be derived from methyl and ethyl acrylate and methyl and ethyl methacrylate. Other conventional comonomers may be present in the copolymers as long as they do not detract from the copolymer's usefulness in the present system. Particularly useful is Eudragit E30D, a polymeric dispersion of a copolymer neutral in character based on poly(meth)acrylic acid ester and having a mean molecular weight of about 800,000. Other useful polymers are ethyl cellulose and cellulose acetate (sold as aqueous dispersions under the names Aquacoat and Surelease). The granulations of the first and second components are carried out separately. In each case wet granulation techniques are followed, using a small amount of water and a surfactant. The second granulation in turn is preferably coated with a water insoluble (meth)acrylate ester copolymer of the type described above, preferably alone or in combination with ethyl cellulose or cellulose acetate. The first and second granulations are then combined in a weight ratio of each to the other of from 10:1 to 1:10, respectively. As will be seen, this ratio can be varied to produce the desired release profile. These are mixed with one or more disintegration excipients operable to effect partial or complete disintegration of the tablet in the stomach. By partial disintegration is meant the partial separation of components of the tablet or erosion of the tablet, leaving a recognizable matrix which continues to disintegrate or to otherwise release the active ingredient, gemfibrozil. Suitable disintegration and erosion excipients include one or more water dispersible cellulose derivatives such as microcrystalline cellulose, water soluble hydroxyalkylcelluloses such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, sodium croscarmelose, polyethylene glycols, sugars, and polyvinylpyrrolidone. The combined granulations and disintegration excipients are then compressed into tablets. Processing aids such as separating agents, plasticizers, stabilizers and lubricants can be added in relatively minor amounts. Useful separating or anti-tackiness agents include kaolin, talc, magnesium trisilicate, silicon dioxide and calcium carbonate. Talc is preferred. Lubricants including magnesium stearate, calcium stearate, zinc stearate, colloidal silicon dioxide, stearic acid, and polyethylene glycol also assist in formulation. Alternatively, the two granulations and disintegration excipients, formulated independently, are compressed in a two layer tablet then using a two layer press punch. Layer 1 consisting of the first granulation is first compressed and layer 2 consisting of the second granulation then is compressed over the first layer. The tablets then are coated. The coating material is one whose solubility characteristics make it insoluble in the mouth but readily soluble in the acid environment of the gastric juices of the stomach. For handling and packaging purposes, it is preferred that the coating substance is polymeric in nature. However, other types of coating materials can be substituted for all or part of the polymeric coating. The following examples will serve to further typify the nature of the invention. EXAMPLE 1 First Granulation A first granulation is prepared from the following components: The foregoing ingredients are mixed and granulated. Second Granulation Independently, a second granulation is prepared from the following components: This granulation is coated with the following composition: The foregoing granulations are then combined into three different formulations having compositions as follows: The three formulations above were subjected to in vitro release analysis yielding the following release profiles:

Claims: A disintegratable formulation of gemfibrozil providing both immediate and sustained release and comprising a tablet compressed from a mixture of (i) a first granulation, (ii) a second granulation, and (iii) a disintegration excipient operable to effect partial or complete disintegration in the stomach, said first and second granulations being present in a weight ratio of each to the other of from 10:1 to 1:10, respectively, said first granulation comprising finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, granulated with at least one cellulose derivative, sugar or polyvinyl pyrrolidone and said second granulation comprising finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, granulated with a pharmaceutically acceptable water soluble or insoluble polymer, said second granulation being uniformly coated with a water insoluble sustaining material comprising a pharmaceutically acceptable (meth) acrylate ester copolymer and/or ethyl cellulose and cellulose acetate prior to admixture with said first granulation. A disintegratable formulation of gemfibrozil according to claim 1 wherein said cellulose derivative of said first granulation includes at least one of microcrystalline cellulose, water soluble hydroxyalkylcelluloses. A disintegratable formulation of gemfibrozil according to claim 2 wherein water soluble hydroxyalkylcelluloses are hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose. A disintegratable formulation of gemfibrozil according to claim 1 wherein said cellulose derivative of said first granulation includes microcrystalline cellulose and hydroxypropyl cellulose. A disintegratable formulation of gemfibrozil according to claim 1 wherein said pharmaceutically acceptable water soluble or insoluble polymer of said second granulation is a pharmaceutically acceptable (meth)acrylate copolymer. A disintegratable formulation of gemfibrozil according to claim 5 wherein said (meth)acrylate copolymer is a copolymer derived from methyl and ethyl acrylate and methyl and ethyl methacrylate having a mean molecular weight of about 800,000. A disintegratable formulation of gemfibrozil according to claim 6 wherein said second granulation is coated with a pharmaceutically acceptable (meth)acrylate copolymer. A disintegratable formulation of gemfibrozil according to claim 7 wherein said (meth)acrylate copolymer is derived from methyl and ethyl acrylate and methyl and ethyl methacrylate and has a mean molecular weight of about 800,000. A disintegratable formulation of gemfibrozil according to claim 1 wherein said disintegration excipients include one or more water dispersible cellulose derivatives. A disintegratable formulation of gemfibrozil according to claim 9 wherein said disintegration excipients are selected from microcrystalline cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and sodium croscarmelose. A disintegratable formulation of gemfibrozil according to claim 10 wherein said disintegration excipients are microcrystalline cellulose and sodium croscarmelose. A process for the manufacturing of a disintegratable formulation of gemfibrozil providing both immediate and sustained release and comprising compressing a tablet from a mixture of (i) a first granulation, (ii) a second granulation, and (iii) a disintegration excipient operable to effect partial or complete disintegration in the stomach, said first and second granulations being present in a weight ratio of each to the other of from 10:1 to 1:10, respectively, said first granulation comprising granulating finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, with at least one cellulose derivative, sugar or polyvinyl pyrrolidone and said second granulation comprising finely divided particles of pure gemfibrozil, or a powder blend of gemfibrozil with excipients, with a pharmaceutically acceptable water soluble or insoluble polymer, coating said second granulation uniformly with a water insoluble sustaining material comprising a pharmaceutically acceptable (meth) acrylate ester copolymer and/or ethyl cellulose and cellulose acetate prior to admixture with said first granulation. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 12 wherein said cellulose derivative of said first granulation includes at least one of microcrystalline cellulose, water soluble hydroxyalkylcelluloses. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 13 wherein water soluble hydroxyalkylcelluloses are hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 12 wherein said cellulose derivative of said first granulation includes microcrystalline cellulose and hydroxypropyl cellulose. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 12 wherein said pharmaceutically acceptable water soluble or insoluble polymer of said second granulation is a pharmaceutically acceptable (meth)acrylate copolymer. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 16 wherein said (meth)acrylate copolymer is a copolymer derived from methyl and ethyl acrylate and methyl and ethyl methacrylate having a mean molecular weight of about 800,000. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 17 wherein said second granulation is coated with a pharmaceutically acceptable (meth)acrylate copolymer. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 18 wherein said (meth)acrylate copolymer is derived from methyl and ethyl acrylate and methyl and ethyl methacrylate and has a mean molecular weight of about 800,000. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 12 wherein said disintegration excipients include one or more water dispersible cellulose derivatives. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 20 wherein said disintegration excipients are selected from microcrystalline cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose hydroxypropyl methyl cellulose, and sodium croscarmelose. A process for the manufacturing of a disintegratable formulation of gemfibrozil according to claim 21 wherein said disintegration excipients are microcrystalline cellulose and sodium croscarmelose.

Inventors: GHEBRE-SELLASSIE, ISAAC, GORDON, ROBERT HARRY, KHAN, SADATH U.
Applicants: WARNER-LAMBERT COMPANY
Application year: 1990
Main classification: A61K31
IPC codes: A61P3, A61K9, A61K31