Formulation, Characterization, and In Vitro Evaluation of Transdermal Patches for Inhibiting Crystallization of Mefenamic Acid.

The crystallization of mefenamic acid in transdermal patch is a major problem that makes the patch unstable and decreases the drug release. The additive was used to inhibit crystallization of a mefenamic acid. Among the different types of additives, polyvinylpyrrolidone (PVP) K30 and PVP K90 were studied and found to be highly effective in inhibiting the crystallization of the drug. The PVP presented as a solubilizer agent for mefenamic acid in matrix patches at the different ratio between drug : PVP, 1 : 2 and 1 : 2.5 for using PVP K30 and 1 : 1.5 and 1 : 2 for using PVP K90. The characterizations showed the homogeneous patches without the crystal form of the mefenamic acid in matrix patches. The release profiles of the mefenamic acid from the patches were investigated by Franz diffusion cells. Over the first 1 h, the release behavior of mefenamic acid from the patches obviously increased when PVP was used as a crystallization inhibitor. However, the ratio between drug : PVP K90 at 1 : 2 was found to be the most effective in increasing the drug release from patch. Thus, the PVP could be used as a crystallization inhibitor for mefenamic acid in matrix patches which will increase the drug release.