Claims for Patent: 5,225,205

Summary for Patent: 5,225,205

Title:	Pharmaceutical composition in the form of microparticles
Abstract:	A method for preparing a pharmaceutical composition in the form of microparticles, the composition thus obtained and its use for preparing injectable suspensions.
Inventor(s):	Orsolini; Piero (Martigny, CH)
Assignee:	Debiopharm S.A. (Lausanne, CH)
Application Number:	07/836,478
Patent Claims:	1. A pharmaceutical composition in the form of microparticles obtained by a method which comprises: Dry-mixing microparticles of a copolymer of lactic and glycolic acids with microparticles of an active substance of a salt of a natural or synthetic peptide comprising 3 to 45 amino acids for a sufficient time to form a homogeneous mixture containing about 0.1 to 15% by weight of the active substance and about 85 to 99.9% by weight of the copolymer, said active substance microparticles having an average grain size of below approximately 10 microns and said copolymer microparticles having an average grain size of below approximately 200 microns; and precompressing and preheating the mixture prior to extruding the precompressed and preheated mixture at a temperature of between approximately 80.degree. and 100.degree. C. and pulverizing the extruded mixture to a particle size of below about 200 microns to form said pharmaceutical composition. 2. The composition of claim 1 in combination with a suitable carrier and in the form of an injectable suspension. 3. The composition of claim 1 wherein the active substance is a pamoate, tannate, stearate or palmitate salt of the natural or synthetic peptide, and wherein the method is characterized in that: the selected copolymer and active substance, both present in the form of microparticles whose average grain size is below approximately 200 and 10 microns, respectively, are dry-mixed; the powdered mixture thus obtained is compressed and is heated up to approximately 80.degree. C.; the precompressed and preheated mixture is subjected to an extrusion at a temperature of between approximately 80.degree. and 100.degree. C.; the product resulting from the extrusion is pulverized at low temperature; and the microparticles having a grain size below approximately 200 microns are collected for use as the pharmaceutical composition. 4. A controlled release, pharmaceutical composition for the prolonged release of a medicamentous substance comprising microparticles having a selected grain size of below approximately 200 microns formed of a copolymer of lactic and glycolic acid in an amount of about 85 to 99.9% by weight; and a pharmaceutically acceptable salt of a natural or synthetic peptide in an amount of about 0.1 to 15% by weight; wherein the peptide is dispersed substantially uniformly throughout the copolymer by being dry-mixed, compressed and heated, extruded and pulverized to the selected grain size. 5. The composition of claim 4 wherein the copolymer is L-lactic/glycolic acid or D,L-lactic/glycolic acid containing 45 to 90% (moles) lactic acid and 55 to 10% (moles) glycolic acid respectively. 6. The composition of claim 4 wherein said copolymer and said peptide are both microparticles having an average grain size of less than 200 and 10 microns, respectively, prior to being mixed. 7. The composition of claim 4 wherein said pharmaceutically acceptable salt of a natural or synthetic peptide is a water insoluble salt of a natural or synthetic peptide having from 3 to 45 amino acids. 8. The composition of claim 7 wherein said peptide is LH-RH, somatostatin, GH-RH, calcitonin or a synthetic analogue/homologue thereof and said pharmaceutically acceptable salt is a pamoate, tannate, stearate, or palmitate salt. 9. The composition of claim 4 wherein said peptide is a water insoluble salt of somatostatin, or LH-RH or analogues or homologues thereof selected from ##STR5## wherein R.sup.1 is a lower alkyl. 10. The composition of claim 4 wherein said peptide is a pamoate, tannate, stearate or palmitate salt of 11. The composition of claim 4 wherein said peptide is a pamoate salt of 12. The composition of claim 4 wherein said peptide is a pamoate, tannate, stearate or palmitate of ##STR6## 13. The composition of claim 12 wherein said microparticles are added to a pharmaceutically acceptable solution to form an injectable suspension. 14. The composition of claim 12 wherein said composition is in the form of an implantable rod. 15. The composition of claim 11 wherein said peptide, when placed in the physiologic environment, is released for a period of at least 25 days at a dose sufficient to reduce serum testosterone to castration levels. 16. The composition of claim 11 wherein said peptide, when placed in the physiologic environment, is released for a period of at least 40 days at a dose sufficient to reduce serum testosterone to castration levels. 17. The composition of claim 9 wherein said peptide is a pamoate, tannate, stearate or palmitate or 18. The composition of claim 17 wherein said composition provides release of said compound from about 7 to about 15 days. 19. The composition of claim 17 wherein said microparticles are added in a therapeutically effective amount to a pharmaceutically acceptable solution to form an injectable suspension. 20. The composition of claim 17 wherein said composition is in the form of an implantable rod.