Sustained release micropellets and process for producing the same

Abstract

Sustained release micropellets showing a stable controlled-release of a drug without being affected by the changes in pH value etc., characterized by being produced by coating core particles with a layer containing a water-soluble drug and further forming a film layer containing a water-insoluble polymer compound and a plasticizer on the thus obtained particles, locating a water-soluble filler layer between the water soluble drug-containing layer and the film layer, and having an average particle size of 300 μm or less; medicinal compositions containing these micropellets; and a process for producing the same.

1 . Sustained release micropellets having an average particle size of 300 μm or less which comprise being produced by coating core particles with a layer containing a water-soluble drug and further forming a film layer containing a water-insoluble polymer compound and a plasticizer on the particles and forming a water-soluble filler layer between the water-soluble drug-containing layer and the film layer.  
     
     
         2 . The sustained release micropellets according to  claim 1 , wherein the weight of the film layer is 20 to 50% of the total weight of the particles and that of the water-soluble filler layer.  
     
     
         3 . The sustained release micropellets according to  claim 1 , wherein the film layer is composed of two or more layers comprising the film layer not containing any water-soluble polymer compound and the film layer containing a water-soluble polymer compound.  
     
     
         4 . The sustained release micropellets according to  claim 1 , wherein the water-soluble drug is a water-soluble analgesic and the water-insoluble polymer compound is ethylcellulose.  
     
     
         5 . The sustained release micropellets according to  claim 4 , wherein the water-soluble analgesic is an opioid analgesic.  
     
     
         6 . The sustained release micropellets according to  claim 5 , wherein the opioid analgesic is morphine or a pharmaceutically acceptable salt thereof.  
     
     
         7 . The sustained release micropellets according to  claim 1 , wherein the layer containing a water-soluble drug, the water-soluble filler layer, and the film layer containing a water-insoluble polymer compound and a plasticizer can be formed by layering or coating using water or an aqueous solution as the solvent.  
     
     
         8 . Medicinal compositions comprising the sustained release micropellets described in  claim 7 .  
     
     
         9 . The medicinal compositions according to  claim 8 , wherein two or more types of sustained release micropellets with different dissolution patterns are contained.  
     
     
         10 . The medicinal compositions according to  claim 8 , wherein the medicinal compositions are any of fine granules, powders and dry syrups.  
     
     
         11 . A process for producing sustained release micropellets having an average particle size of 300 μm or less which comprises producing coated particles by coating core particles with a layer containing a water-soluble drug and further forming a film layer containing a water-insoluble polymer compound and a plasticizer on the particles, and locating a water-soluble filler layer between the water-soluble drug-containing layer and the film layer.  
     
     
         12 . The process for producing sustained release micropellets according to  claim 11 , wherein the weight of the film layer is 20 to 50% of the total weight of the coated particles and the water-soluble filler layer.  
     
     
         13 . The process for producing sustained release micropellets according to  claim 11 , wherein the film layer is composed of two or more layers including the film layer not containing any water-soluble polymer compound and the film layer containing a water-soluble polymer compound.  
     
     
         14 . The process for producing sustained release micropellets according to  claim 11 , wherein the water-soluble drug is a water-soluble analgesic and the water-insoluble polymer compound is ethylcellulose.  
     
     
         15 . The process for producing sustained release micropellets according to  claim 14 , wherein the water-soluble analgesic is an opioid analgesic.  
     
     
         16 . The process for producing sustained release micropellets according to  claim 15 , wherein the opioid analgesic is morphine or pharmaceutically acceptable salt there of.  
     
     
         17 . The process for producing sustained release micropellets according to  claim 11 , wherein the layer containing a water-soluble drug, the water-soluble filler layer, and the film layer containing a water-insoluble polymer compound and a plasticizer can be formed by layering or coating using water or an aqueous solution as the solvent.  
     
     
         18 . The process for producing a medicinal composition containing the sustained release micropellets according to  claim 17 .  
     
     
         19 . The process for producing a medicinal composition according to  claim 18 , wherein the composition contains two or more types of sustained release micropellets with different dissolution patterns.  
     
     
         20 . The process for producing the medicinal compositions according to  claim 18 , wherein the medicinal compositions are any of fine granules, powders and dry syrups.