| 摘要 |
1,255,416. Making beadlets. SUMITOMO CHEMICAL CO. Ltd. 7 March, 1969 [11 March, 1968], No. 12246/69. Heading A5B. [Also in Division B8] Beadlets comprising one or more particles or droplets of a solid or liquid "active" substance encased within a larger particle of a film-forming, gelible, hydrophilic substance are prepared by: i) forming an aqueous emulsion or suspension of the active substance (with or without an emulsifier/supending agent), ii) adding thereto an aqueous solution of a gelable hydrophilic substance, iii) forming a dispersion in this system of a solvent which is immiscible with the aqueous phase of the system with the aid of a surfactant which is added to either phase, iv) converting the dispersion thus obtained to a system wherein droplets of the original emulsion or suspension exist in a continuous phase of the immiscible solvent by addition of further immiscible solvent (same or different) or by raising the temperature or by addition of multivalent metal ions (this step being carried out at a temperature above the gelation point of the hydrophilic substance) and cooling the mixture to below the said gelation point. The beadlets may be washed, hardened and dried by conventional methods and may be employed when a delayed or gradual release of the active substance is desired. A wide variety of active substances, and hydrophilic substances and suitable surface active agents are mentioned and specific examples relate to the encapsulation of vitamin A, #-carotene, linoleic acid, vitamin D 2 (in peanut oil), ascorbic acid (dispersed in edible fat), hydrocortisone acetate, methyl salicylate, peppermint oil, peanut oil, petroleum spirit and trichlorodiphenyl. The preferred gelable substance is gelatin. |
