Method of producing micro-capsules for the sustained release of drugs

Abstract

Micro-capsules for the slow release of drugs, consisting of a lactic-co-glycolic copolymer to which a plasticiser has been incorporated and which contain a drug of pharmaceutical interested within them.

1 - 11 . (canceled)  
     
     
         12 . A method for producing microcapsules which comprises the steps of: 
 a) dissolving a lactic co-glycolic copolymer and a citric acid ester derivative in a solvent in which said lactic co-glycolic copolymer and said citric acid ester derivative are soluble to form a solution;    b) adding a peptide of pharmaceutical interest to the solution to form a peptide suspension in said solution;    c) adding an alkyl derivative to the solution to produce deposition of the lactic co-glycolic copolymer and the citric acid ester derivative on the peptide;    d) adding the suspension obtained in step (c) to a solution in which said lactic co-glycolic copolymer and citric acid ester are not soluble to harden and precipitate microcapsules thus formed; and    e) isolating the microcapsules thus formed;    wherein said citric acid ester derivative is added in an amount sufficient to regulate the release rate of said peptide of pharmaceutical interest from said microcapsules once said microcapsules are within the body of a subject.    
     
     
         13 . The method for producing microcapsules according to  claim 12 , wherein the citric acid ester used in forming said microcapsules is selected from triethyl citrate, tributyl citrate and acetyl tributyl citrate.  
     
     
         14 . The method for producing microcapsules according to  claim 13 , wherein the citric acid ester used in forming said microcapsules is triethyl citrate.  
     
     
         15 . The method for producing microcapsules according to  claim 14 , wherein the amount of said triethyl citrate is between 0.1% and 60% by weight of the copolymer.  
     
     
         16 . The method for producing microcapsules according to  claim 12 , wherein the ratio between lactate and glycolate units n the lactic co-glycolic copolymer is between 100:0 and 10:90, both inclusive.  
     
     
         17 . The method for producing microcapsules according to  claim 16 , wherein said alkyl derivative is silicon oil.  
     
     
         18 . The method for producing microcapsules according to  claim 12 , wherein the peptide of pharmaceutical interest encapsulated within said microcapsules is an analogue of LHRH.  
     
     
         19 . The method for producing microcapsules according to  claim 18 , wherein the analogue of LHRH encapsulated within said microcapsules is selected from tryptoreline, leuprolide, gosereline, busereline and cetrorelix.  
     
     
         20 . The method for producing microcapsules according to  claim 12 , wherein the peptide of pharmaceutical interest encapsulated within said microcapsules is somatostatine or an analogue thereof.  
     
     
         21 . The method for producing microcapsules according to  claim 20 , wherein the analogue of somatostatine encapsulated within said microcapsules is octreotide.  
     
     
         22 . The method for producing microcapsules according to  claim 12 , wherein the peptide of pharmaceutical interest encapsulated within said microcapsules is analogue of human calcitonine.  
     
     
         23 . The method for producing microcapsules according to  claim 22 , wherein the analogue of human calcitonin encapsulated within said microcapsules is salmon calcitonine or carbocalcitonine  
     
     
         24 . A pharmaceutical composition comprising microcapsules prepared according to  claim 12  and a pharmaceutically acceptable carrier.