ENCAPSULATED MICROCAPSULES

A microencapsulation procedure has been developed which allows an oil slurry of microcapsules to be filled into soft gelatin capsules. Ethylcellulose solutions in ethyl acetate can be desolvated by the addition of light liquid paraffin so that an ethylcellulose coat is deposited on a core material such as aspirin. Approximately 1% of the aspirin is imperfectly encapsulated. The use of light liquid paraffin enables the slurry to be filled directly into soft gelatin capsules without the usual filtering, drying, and redispersion steps. Different release characteristics can be devised by varying the ratio of ethylcellulose to drug. In vitro release into a simulated gastric juice shows that essentially first-order kinetics exist for periods up to 12 hours. © 1979.