Evaluation of seed flour of Vigna mungo (L.) based sustained release matrix tablets of diclofenac sodium.

This study concerns the evaluation of seed flour of Vigna mungo or black gram as sustained release matrix forming material in tablet formulation. The physicochemical properties of seed flour of black gram such as swelling index, hydration capacity, powder porosity, loss on drying, pH and viscosity were studied. Matrix tablets were prepared by wet granulation technique using isopropyl alcohol as a granulating agent. Diclofenac sodium was used as a model drug. Sustained release matrix tablets of diclofenac sodium, were developed by using different drug: polymer ratios, such as BF1 (1:1), BF2 (1:2), BF3 (1:3) and BF4 (1:4). All the lubricated formulations were compressed using flat faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness, thickness, in vitro dissolution using paddle method, and swelling behavior. All the formulations showed compliance with pharmacopoeial standards. Among different formulations, F1 showed sustained release of drug for 12 hours with 92.44% release. Tablets prepared with Hydroxypropylmethylcellulose (HPMC 50cps) and Xanthan gum as matrix forming material for the comparative study. The dissolution profiles of the HF2 and XF1 matrix tablets were close to the profile obtained by seed flour of black gram based matrix tablets BF1. The selected formulation (BF1) was subjected to stability studies for three months at 45° temperature with RH 75±5%, and showed stability with respect to release pattern. The kinetic treatment showed that the release of drug follows zero order model and anomalous diffusion for BF1 and XF1 while the drug release of HF2 was best explained by Higuchi’s model and anomalous diffusion. It is concluded that seed flour of black gram possess substantial matrix forming property that could be used for sustained drug delivery.