Production method for sustained-release preparation

Abstract

This invention provides a production method for a solid sustained-release preparation, characterized in that a sustained-release preparation (a sustained-release preparation suspension) is freeze-dried in a freeze-drying container whose inner face is partially or totally coated with an ice layer or water-repelling base material.

1 . A method for producing a solid sustained-release preparation, which comprises freeze-drying a sustained-release preparation in a freeze-drying container of which the inner face is partially or wholly coated with an ice layer or water-repelling base material: 
 wherein the ice layer has a thickness of about 0.1 mm to about 30 mm; and    wherein the water-repelling base material is ethylene tetrafluoride resin, ethylene trifluoride resin, ethylene difluoride resin, vinylidene fluoride resin, propylene hexafluoride-ethylene tetrafluoride copolymer resin, modified fluorine resin, ethylene tetrafluoride-perfluoroalkoxyethylene copolymer resin, or ethylene tetrafluoride-ethylene copolymer resin.    
     
     
         2 . A method for producing a solid sustained-release preparation, which comprises freeze-drying a sustained-release preparation in a freeze-drying container of which the inner face is partially or wholly coated with a water-repelling base material, and the coated inner face is further partially or wholly coated with an ice layer.  
     
     
         3 . The method according to  claim 1  wherein the inner face is the bottom face alone.  
     
     
         4 . The method according to  claim 1  wherein the freeze-drying container is a tray.  
     
     
         5 - 6 . (canceled)  
     
     
         7 . The method according to  claim 1  wherein said sustained-release preparation is a microsphere.  
     
     
         8 . The method according to  claim 1  which comprises completing the sublimation of frozen water in the freeze-drying container under reduced condition that the temperature in the freeze-drying container is 0° C. or below.  
     
     
         9 . The method according to  claim 3  wherein said sustained-release preparation is a microsphere.  
     
     
         10 . The method according to  claim 4  wherein said sustained-release preparation is a microsphere.  
     
     
         11 . The method according to  claim 2  wherein the inner face is the bottom face alone.  
     
     
         12 . The method according to  claim 2  wherein the freeze-drying container is a tray.  
     
     
         13 . The method according to  claim 2  wherein said sustained-release preparation is a microsphere.  
     
     
         14 . The method according to  claim 2  which comprises completing the sublimation of frozen water in the freeze-drying container under reduced condition that the temperature in the freeze-drying container is 0° C. or below.