Locust bean gum as superdisintegrant--formulation and evaluation of nimesulide orodispersible tablets

Orodispersible tablets disperse instantaneously in the mouth so that they can be swallowed without the aid of water. The aim of the present study was to formulate nimesulide orodispersible tablets using locust bean gum as a natural superdisintegrant. The gum was evaluated for powder flow properties, swelling index and loss on drying. Excellent powder flow properties were observed, swelling index was found to be 20 which indicated appreciable capability of locust bean gum to be used as superdisintegrant. The prepared tablets were evaluated against standard superdisintegrant i.e. cross-carmellose sodium. Disintegration time of tablets containing 10 % locust bean gum was found to be 13 seconds. The prepared batches were also evaluated for wetting time, water absorption ratio, effective pore radius, porosity, in vitro and in vivo disintegration time, in vitro release and stability studies. Wetting time was found to reduce from 19 +/- 2 to 11 +/- 3 sec (A1-A4) and 51 +/- 2 to 36 +/- 3 sec (B1-B4). Effective pore radius and porosity were found to be increase with increase in polymer concentration. The superdisintegrant property of locust bean gum may be due to concentration dependent wicking action leading to formation of porous structure which disintegrates the tablet within seconds. In-vivo results were complementary to in-vitro disintegration time results. The in-vitro release studies were compared against marketed nimesulide fast dissolving tablets (Nimulid MD). Stability studies showed that there was no significant change in hardness, friability, tensile strength and assay of the prepared formulations. The f2 values (in comparison with Nimulid MD) of 92.27 and 98.19 were obtained with A3 and A4 batches respectively.