Studies on the drug release properties of nano-encapsulated indomethacin microparticles.

Indomethacin micro-crystals sized approximately 2 microm have been encapsulated with polyelectrolyte multi-layers for the purpose of controlled release. Charged linear poly (dimethyldiallyl ammonium chloride) (PDDA) and poly (styrene sulphonate) (PSS) were alternatively deposited on approximately 2 microm drug micro-crystals. The release of indomethacin from coated micro-crystals was measured in aqueous solutions of pH 1.4 and 6.8. The polyelectrolyte multi-layer capsule thickness was proved to control. The results provided a method of achieving prolonged drug release through self-assembly of polymeric shells on drug microcrystals.