Preparation of capsules containing a hydrophilic physiologically active substance with tripalmitin and soybean lecithin

Capsules were prepared by using the mixed system of fatty acid ester (tripalmitin) and soybean lecithin as a capsule matrix. A hydrophilic physiologically active substance (L-Cystein) as the core material was encapsulated. Lecithin was added into tripalmitin in order to improve stability of core material in the matrix and water-resistant property of the matrix. Oil droplets made from lecithin and tripalmitin were dispersed in an aqueous solution of methyl cellulose (MC), and solidified by cooling down. It was investigated how the preparation conditions affected the properties of capsules. As the mixture ratio of lecithin to tripalmitin increased, the capsule size, the encapsulation efficiency and the content of core material were increased. Furthermore, it was found that the release rate of core material could be repressed by increasing the mixture ratio.