Development and Evaluation of Flupirtine Maleate Transdermal Patch Containing Different Permeation Enhancers

The present study was aimed at the formulation of transdermal patches of flupirtine maleate containing different permeation enhancers. It acts indirectly as N-methyl-D-aspartate (NMDA) receptor antagonist and activates the K+ channels; thereby acts as a skeletal muscle relaxant. Flupirtine maleate transdermal patches are intended to provide localized effect. The patches were prepared by solvent evaporation technique, using polyvinyl alcohol (PVA) as the polymer whereas dimethyl sulfoxide (DMSO) and polyethylene glycol (PEG-400) as the permeation enhancers. Methanol was used as a solvent to dissolve the drug and glycerol was used as the plasticizer. These patches were evaluated for in vitro permeation, tensile strength, percent moisture absorption, drug content uniformity, film thickness, weight variation and folding endurance. All the patches showed extended release properties. Formulation FDD8 containing 8% polymer and 2% DMSO was found to be the optimized formulation on the basis of evaluation parameters. In vitro permeation release was found to be 95.71 ± 0.01% at the end of 12 h. As the concentration of DMSO increased, the release profile of drug was enhanced. This indicated that DMSO improved the release profile of flupirtine maleate when compared to PEG-400. The release kinetics of the transdermal patches followed Higuchi matrix model. The stability studies showed that all the optimized patches were stable during their study period. From the present study, it can be concluded that addition of DMSO yields good result to enhance the permeation of the drug. Keywords: flupirtine maleate, transdermal patch, permeation enhancers, dimethyl sulfoxide DMSO, polyethylene glycol PEG-400, polyvinyl alcohol PVA.