FACTORIAL STUDIES ON THE ENHANCEMENT OF DISSOLUTION RATE OF NIMESULIDE TABLETS EMPLOYING STARCH CITRATE - A NEW MODIFIED STARCH, PEG 4000 AND PVP K- 30

Nimesulide, a potent widely prescribed anti-inflammatory and analgesic drug belongs to class-II under BCS and exhibit low and variable oral bioavailability due to its poor aqueous solubility. Solid dispersion of nimesulide in starch citrate, a new modified starch and two solubilizers namely PEG 4000 and PVP K-30 were investigated to enhance the dissolution rate of nimesulide tablets in a 23 - factorial study. The individual main and combined effects of the three factors namely PEG 4000 (factor A), PVP K- 30 (factor B) and starch citrate (factor C) in enhancing the dissolution rate and dissolution efficiency of nimesulide tablets were evaluated. The individual as well as combined effects of the three factors in enhancing the dissolution rate (K1) are highly significant (P<0.01) except the combined effect of ABC. The order of increasing enhancement in the dissolution rate of nimesulide tablets with various factors was C (starch citrate, 10.18 fold) > B (PVP K-30, 3.25 fold) > A (PEG 4000, 1.43 fold). Among the combined effects, combination of AC (Fac) gave highest enhancement in dissolution rate, K1 (13.62 fold) and in DE30 (3.66 fold). Solid dispersion of nimesulide in starch citrate has significantly enhanced the dissolution rate (10.08 fold) and DE30 (3.52 fold) of nimesulide tablets. Combination of factors A and C i,e solid dispersion of nimesulide in starch citrate along with PEG 4000, has further enhanced the dissolution rate (13.62 fold) and DE30 (3.66 fold) of nimesulide tablets. Formulations Fc and Fac gave more than 90% dissolution in 15 min.