Evaluation of Colocasia antiquorum gum in sustained release of diphenhydramine HCl and theophylline hydrate tablet formulations

The objective of this work was to develop direct compression matrix sustained-release tablets of diphenhydramine HCl and theophylline hydrate using Colocasia antiquorum gum (CAG) extracted by cold maceration as binder. Phytochemical characteristics of the gum were evaluated and different ratios of CAG were applied in the formulations. The physical characteristics and in vitro release profile performed in phosphate buffer medium (pH 7.4) of the tablets were determined to assess the suitability of the gum in the sustained release formulations of the drugs. The gum showed a fine bland, tasteless, brownish white powder with poor aqueous solubility in water; with presence of starch and saponin. Of the formulations only the T2 batch containing 16.67 % of the CAG in theophylline sustained release for 8 h making it a suitable binder for formulations at this concentration and mixed results in the dissolution profile of the two drugs in their mechanism and kinetics of release.