Microencapsulation for controlled oral drug delivery system

摘要

A process for the microencapsulation of oil droplets containing a medical drug for oral administration, comprises the steps of mixing the drug with liquid oil by sonication for 5-30 seconds to disperse the drug homogeneously in the oil, and adding the drug-dispersed oil to an aqueous solution mixture to form a two phase system. The aqueous solution mixture will form a capsule material, and comprises a polysaccharide which has metal chelating capacity, a biocompatible and water-soluble polymer for improving the physical properties of the capsule material, and emulsifying agents. The two phase system is then subjected to sonication to produce an oil-in-water emulsion containing the drug-dispersed oil in the form of droplets having a diameter in the range of 1-5 mu m. As soon as possible after formation of the emulsion, the emulsion is added to a multivalent cation-containing solution to harden the capsule material. The microencapsulated emulsion is then freeze-dried to obtain a final product in a powdery state.