Sustained Release of a Water-Soluble Drug from Directly Compressed Okra Gum Matrix Tablets

Okra gum was evaluated as a controlled-release agent in modified release matrices in comparison with sodium carboxymethylcellulose (NaCMC) using aspirin as the model drug. Tablets were produced by direct compression and the in vitro drug release was assessed under conditions similar to those in the gastrointestinal system for a period of 6 hours. The hydration (swelling) and erosion rates of the okra gum matrix tablets were also studied. Okra gum matrices provided a controlled-release of aspirin and the release rates followed time-independent kinetics. The addition of the tablet excipients, lactose and Avicel, altered the dissolution profile and release kinetics. Okra gum compared favourably with NaCMC and a combination of okra gum and NaCMC resulted in near zero-order release of aspirin from the matrix tablets. The results indicate that okra gum is suitable for the sustained release of water soluble drugs. Keywords : Okra gum, aspirin, matrix tablet, sustained-release The East and Central African Journal of Pharmaceutical Sciences Vol. 9 (2) 2006: pp. 46-51