In vitro evaluation of theophylline matrices using xyloglucan

Xyloglucan is a water soluble polysaccharide extracted from the beans of Tamarindus Indica. Very few publications are found related to its use for preparing oral sustained release swellable matrix. The purpose of this investigation was to prepare sustained release matrices using Xyloglucan and investigate the effects of polymer level, diluents type, pH and ionic strength of the dissolution medium, basket rotational speed, and swelling isotherms on drug release. Tablet formulations containing 50% theophylline as a drug model, Xyloglucan cold water soluble (20%, 30 and 40%) and different diluents (Avicel PH-101, lactose and dibasic calcium phosphate) were prepared. The formulation containing 30% Xyloglucan water soluble and Avicel was selected as best formulation because it gives controlled release profile and tested for swelling isotherms, drug release in different dissolution media, and different basket rotational speed. Percent drug release from formulations containing 50% theophylline, 30% Xyloglucan water soluble, and Avicel PH-101 was 34.2% at 6 hours, 35.6% with lactose, and 30.9% with Emcompress. ANOVA two-way analysis showed a change in drug release rate when polymer percent was increased at the 5% significance level. Different diluents, different dissolution media, and different basket rotational speeds did not significantly change the drug release. The mechanism of drug release appears to follow anomalous relaxation for swellable matrix.