Formulation, Development and Characterization of Transdermal Patches of Sitagliptin Phosphate

Abstract

Sitagliptin is a dipeptidyl peptidase 4-(DPP-4) inhibitor with glucose controlling capabilities that was effectively used for treating diabetes in the past. However, the oral administration of this drug caused such severe side effects that it was removed from the market. Transdermal patches are innovative drug delivery systems and can be used for achieving efficient systemic effect by passing hepatic first pass metabolism and increasing the fraction absorbed. Transdermal patches of Sitagliptin phosphate (SIT) were prepared by the solvent casting evaporation technique using ethyl cellulose: HPMC, Eudragit RLPO, propylene glycol and permeation enhancer using different ratios. The physicochemical parameters such as flexibility, thickness, smoothness, weight variation, moisture content, hardness, folding endurance and tensile strength were evaluated for the prepared patches. The formulation exhibited flexibility, uniform thickness and weight, smoothness, good drug content (95.65to 99.45%) and little moisture content. The in vitro diffusion studies were carried out using modified Franz diffusion cell using egg membrane as the diffusion membrane and the formulation followed the Higuchi diffusion mechanism. The formulation containing ethyl cellulose: HPMC as polymers showed faster release rate compared to Eudragit: HPMC.  The stability studies indicated that all the patches maintained good physicochemical properties and drug content after storing the patches in different storage conditions. Compatibility studies indicated that there was no interaction between the drug and polymers. Hence, the aim of the present study was to prepare the sustained release formulation (Transdermal patches) of the drug using different blend of polymers. Keywords: Transdermal patches, Sitagliptin phosphate, Physicochemical parameters, in vivo study