7. Formulation and in vitro release properties of a plant gum obtained from sesamum indicum (Fam. pedaliaceae)

The formulation properties of a plant gum obtained from Sesamum indicum were studied. Physicochemical characterisation of the gum was done by carrying out solubility test, loss on drying, total ash and acid insoluble ash determination, pH determination, swelling characteristics and micromeritic properties. Tablets were prepared by incorporating an antifilarial drug, Diethylcarbamazine (DEC). In vitro drug release studies were carried out in simulated gastric and intestinal conditions. Effect of gum concentration on release kinetics was evaluated. The moisture content of Sesamum indicum Gum (SIG) was low, suggesting its suitability in formulations containing moisture sensitive drugs. The total ash and acid insoluble value of SIG was found to be 2.0 and 1.0 %w/w respectively. The swelling was highest in water followed by phosphate buffer and least in 01N HCI pH (5.0, 4.0 and 3.0 respectively). All the DEC tablets formulated with SIG as binder were of good mechanical strength and acceptable friability values. Release of DEC in simulated biological fluids varied between 2 to 8 hours depending on the concentration of gum used in the formulation. From the results, all the formulations followed zero order kinetics with highest linearity (r2 = 0.9709, 0.9743, 0.9716, 0.9727) via non-Fickian (anomalous) mechanism. All the formulations released the drug in the hydrated matrix through polymer relaxation. There was no significant difference(P>0.05) in drug release among the formulations, SIG 10 %, SIG 20 %, SIG 30 %, and NaCMC 30 % . Release profile of SIG 30 % and the reference gum, NaCMC 30 % were very similar (P> 0.01). The findings of this research establish the fundamental characteristics of Sesamum indicum gum (SIG). The matrices responded to changes in pH along the GIT. This implies that the gum can be used for intestinal drug delivery.