Formulation Development of Nimesulide Tablets by Wet Granulation and Direct Compression Methods employing Starch PhosphateAuthor(s): K. P. R. Chowdary, Veeraiah Enturi and P. Siva Kumar
Nimesulide, a widely prescribed anti-inflammatory analgesic drug belongs to BCS class II and exhibit low and variable oral bioavailability due to its poor solubility and dissolution rate. The objective of the present study is to develop nimesulide rapidly dissolving tablet formulations by wet granulation and direct compression methods employing starch phosphate, a new modified starch. As per FDA guidelines on biowaivers, drug products containing weakly acidic BCS class II drugs with a dissolution of > 85% in 30 min are eligible for biowaiver. Hence, a dissolution of > 85% in 30 min is taken as target dissolution to achieve in the formulation development of nimesulide tablets. Starch phosphate prepared by reacting potato starch with disodium hydrogen orthophosphate anhydrous at elevated temperatures was insoluble in water and has good swelling (400%) property without pasting or gelling, when heated in water. In the micromeritic evaluation, the angle of repose and compressibility index values revealed the excellent flow characteristic of starch phosphate prepared. All the physical properties studied indicated that starch phosphate is a promising pharmaceutical excipient in tablets. Nimesulide rapidly dissolving tablets with >85% dissolution in 30 min could be formulated employing starch phosphate as directly compressible vehicle by direct compression method (BF3) and also employing nimesulide-starch phosphate (1 : 2) solid dispersion by wet granulation method (BF4). Formulations BF3 and BF4, respectively gave 90.25% and 97.25% dissolution in 30 min fulfilling the target dissolution requirement for biowaiver.