| 摘要 |
1364815 Microcapsules TOYO JOZO CO Ltd 29 Dec 1972 [30 Dec 1971] 59941/72 Heading B8C Microcapsules are prepared by dissolving or dispersing a core substance in a solution of a film-forming polymer, emulsifying the product in a liquid vehicle which is poorly miscible with the polymer solvent and adding to the emulsion a non-solvent for the polymer which is miscible with the solvent but only poorly miscible with the vehicle, whereby solvent is removed from the emulsified particles thereby to cause encapsulation of the core material in the polymer. Various core materials are mentioned, specific examples relating to pancreatin powder, phosphatase, lipase, glycolysis enzymes, urease, activated carbon and dried micro-organisms (Fusarium solani), the physiologically active substances thereby being converted into enteric forms. Many polymers are mentioned including cellulose derivatives, shellac, polyurethanes, polyacrylates, polyvinyls, gelatine, gum arabic, polystyrene, polyesters and co-polymers. The vehicle may be lipophilic (e.g. paraffin or silicone oil) or hydrophilic (e.g. ethylene glycol, aqueous gelatine solution or formamide), the solvent and non-solvent being chosen according to the nature of the polymer and the vehicle (e.g. benzene as solvent) and nhexane or petroleum ether as non-solvent with an ethylene glycol vehicle and polystyrene or polyester polymer. A finely divided solid, e.g. silica may be present to facilitate formation of a stable emulsion, this becoming incorporated into the microcapsule walls. |
