An Approach for Improvement of the Water Solubility of Nimesulide in Solid Dispersion with Peg

INTRODUCTION Many drugs show bioavailability problems due to their low water solubility, slow dissolution rate, and instability in the gastrointestinal tract. Nimesulide is a non-steroidal anti-inflammatory, analgesic and antipyretic agent, chemically is N-(4 nitro-2-phenoxyphenyl) methane sulfonamide. It is poorly soluble in water and irregularly absorbed by gastrointestinal tract. Among the various approaches to improve the dissolution of poorly soluble drugs, the preparation of solid dispersions has often to be successful [1]. Solid dispersion (SD) is defined as the dispersion of one or more active ingredients in inert carriers at solid state prepared by fusion, solvent, or solvent-fusion methods. In solid dispersions, the particle size of the drugs was reduced, wettability and the dispersibility of the drugs were enhanced; therefore, drug dissolution was improved markedly. Solid dispersion is a promising approach to improve the dissolution and bioavailability of drugs [2]. The methods utilized in the preparation of solid dispersion include melting, use of common solvent and a combination of melting and solvent approach. Various hydrophilic carriers, such as polyethylene glycols, polyvinyl pyrrolidone, and hydroxyl propyl methylcellulose have been Investigated as carriers for solid dispersions, improvement of dissolution characteristics and bioavailability of poorly aqueous-soluble drugs. Solid dispersion prepared from soluble carriers such as polyethylene glycol, usually have the disadvantage of being tacky and therefore difficult to subdivide and handle. PEG solid dispersions were formulated using combinations of melting and solvent approach in which the melted drug and carrier mixture were granulated with excipients that result less tacky granulation.