Studies in topical application of niosomally entrapped Nimesulide.

PURPOSE A niosome based transdermal drug delivery system of Nimesulide (NIM) was developed and extensively characterized and evaluated for in-vitro performance followed by in-vivo evaluation in rats by carrageenan induced rat paw edema method. METHOD Niosomes were prepared by lipid film hydration technique using tweens and spans. Preparation of niosomes was optimized for highest percent drug entrapment (PDE). The prepared niosomes were incorporated into 1 percent carbopol gel base and the system was evaluated for drug diffusion across human cadaver skin (HCS) using modified validated diffusion cell. The drug retention studies in niosomes were performed at refrigerated temperature (2 degrees C - 8 degrees C) and at room temperature (25 degrees C+/-2 degrees C) for the period of 2 months. In-vivo performance of plain drug gel, niosomally-entrapped drug in carbopol gel base and marketed formulation were evaluated using acute rat paw edema method. RESULTS Highest mean percentage edema inhibition (PEI) was observed for niosomal nimesulide gel after 24 hours i.e. 66.68 percent +/- 5.19 percent compared to plain drug gel i.e. 12.57 percent +/- 1.78 percent and marketed NIM formulation i.e. 20.49 percent +/- 0.91 percent. CONCLUSION Findings of this investigation conclusively demonstrate prolongation of drug release and increase in amount of drug retention into the skin and permeation across the skin after niosomal encapsulation of NIM. Developed nimesulide niosomal gel formulation has also demonstrated enhanced anti-inflammatory activity compared to plain drug gel and marketed formulation.