Grewia polysaccharide as a pharmaceutical excipient in matrix tablets

Matrix-based tablets using different concentrations of grewia gum, and the model drug ibuprofen, were
prepared using a wet granulation technique. Similar formulations were also prepared using HPMC, guar gum
or ethyl cellulose as the polymer matrix. In addition to tablet properties, swelling and erosion of tablets and
kinetics of drug release were also investigated. In vitro drug release studies, in phosphate buffer (pH 7.2) using
USP type II apparatus, revealed that grewia gum at concentrations of 16%, 32% and 48% can sustain the
release of ibuprofen tablets for up to 24 hours. Release profiles were similar to those tablets containing ethyl
cellulose as the matrix former. Swelling and erosion of grewia gum matrices occurred simultaneously, and
ibuprofen release was by anomalous diffusion in accordance with the Korsmeyer-Peppas model. There was
evidence suggesting synergism between grewia gum and guar gum in sustaining the release of ibuprofen from
tablets when used in the ratio 2:1. Grewia gum may therefore prove a useful excipient, when used on its own,
or in combination with other polymers, to modify drug release