Formulation development and evaluation of nimesulide transdermal gel patch system

The objective was to develop a reservoir-type nimesulide gel patch for controlled drug delivery and avoid the gastrointestinal adverse effects associated with the oral delivery of nimesulide. Six patch formulations of nimesulide gel comprising of 20–40% for ethanol and 20–40% for propylene glycol as permeation enhancers were constructed. Carbopol 934 was used as a gelling agent. The reservoir compartment of transdermal patch was filled with the gel. The in vitro release and skin permeation were assessed using USP apparatus V. The optimized formulation was obtained on the basis of the in vitro drug release and permeation results. The surface area of optimized formulation (F3) was reduced to 1 cm2, and permeation of drug was determined through Franz diffusion cell using Strat-M transdermal diffusional membrane. The nimesulide reservoir patch was placed in the donor compartment. The receptor compartment was filled with 5 mL of permeation medium [normal saline containing 20% v/v PEG-400 was used as dissolution media (pH 7.4)] stirred by magnetic stirrer. The skin sensitivity reaction of the optimized patch was evaluated by Draize method. The formulation F3 comprising of 40% ethyl alcohol and 20% propylene glycol was considered optimized due to maximum % of drug release (86.3 ± 2.73%) and permeation of (3048.84 ± 17.23 µg/cm2), having flux of 449.92 µg/cm2 h and lag time of 0.197 h with no visible skin sensitivity reaction. The study demonstrates that the reservoir-type transdermal patch of nimesulide gel has the potential of delivering drug across the skin in a controlled release manner.