Cross-linked guar gum hydrogel discs for colon-specific delivery of ibuprofen: formulation and in vitro evaluation.

Hydrogel discs of guar gum cross-linked with glutaraldehyde were prepared as vehicles for colon-specific drug delivery. Ibuprofen was chosen as model drug. The discs were evaluated for such parameters as size, shape, weight, and drug loading. Swelling (buffer uptake) and in vitro drug release study, in presence and absence of rat caecal contents, was performed in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) to evaluate the effect of various formulation parameters like guar gum concentration, amount of cross-linking agent, and cross-linking time on drug release. Cross-linking resulted in significant reduction in swelling of guar gum. Significant increase in drug release was observed in medium containing rat caecal content. Percent drug release increased with increasing glutaraldehyde concentration. Cross-linking time and guar gum concentration did not have any significant effect on drug release in the range studied.