Drug Release Characteristics of Ternary Mica/Phosphatidylcholine/Drug Intercalation Compounds

The intercalation of layered inorganic materials, synthetic mica (TSM), with drugs and their drug release characteristics were investigated using intermediate intercalation compounds with phosphatidylcholine (H-PC). Oil-soluble indomethacin and water-soluble imipramine chloride were selected as model drugs. The drug intercalation compounds were prepared by two methods. The first one was the "solvent method" in which the intermediate intercalation compound of TSM with H-PC was prepared in advance using a chloroform solution of H-PC. The intermediate was then mixed with a drug and heated at 180°C to prepare the ternary TSM/H-PC/drug compound. The second one was the "heating method" in which the mixture of (TSM+H-PC+drug) was heated at 180°C to prepare TSM/H-PC/drug directly. The release rate was controlled using a disintegrator (L-HPC). In the case of a tablet sample, the release rate indomethacin was controllable from 60 min (10% L-HPC) to longer than 420 min (3% L-HPC) in the case of the solvent method. A similar result was obtained in the case of imipramine chloride.