Microencapsulation for controlled oral drug delivery system

A microencapsulated emulsion comprising a drug-dispersed oil core, the oil core comprising a drug incorporated into a liquid oil in an amount of approximately 1-40% by weight of the oil, the oil core being surrounded by a water-insoluble capsule material present in an amount of approximately 100-200% by weight of the total weight of the oil core, said capsule material comprising

• a polysaccharide which has metal chelating capacity,
• a biocompatible and water-soluble polymer for improving the physical properties of the capsule material, said polymer being chosen from the group consisting of hydroxypropyl methylcellulose, water-soluble polyamino acid, the sodium salt of polyacrylic acid and collagen;
• and
• emulsifying agents in an amount of approximately 5-10% by weight of the total amount of the capsule material and oil core,
• the droplet size of the microencapsulated emulsion being approximately 1-5.mu.m, the weight ratio of polysaccharide to polymer in the capsule material being at least 0.25.