Formulation, optimization, and evaluation of a transdermal patch of heparin sodium

The purpose of this research was to develop a matrix-type transdermal therapeutic system containing drug heparin sodium with different ratios of hydrophilic polymeric systems by the solvent evaporation technique by using 30% (w/w) of PEG 400 LR to the dry polymer weight, incorporated as plasticizer. Different concentrations of oleic acid and isopropyl myristate were used to enhance the transdermal permeation of heparin sodium. The physicochemical compatibility of the drug and the polymers studied by differential scanning calorimetry and infrared spectroscopy suggested absence of any incompatibility. Formulated transdermal films were physically evaluated with regard to thickness, weight variation, drug content, flatness, tensile strength, folding endurance, percentage of moisture content and water vapour transmission rate. All prepared formulations indicated good physical stability. In-vitro permeation studies of formulations were performed by using diffusion cell apparatus. Formulation prepared with hydrophilic polymer containing permeation enhancer showed best in-vitro skin permeation through Wistar albino rat skin as compared to all other formulations. Formulation F9 showed highest flux among all the formulations and 1.369-fold enhancements in drug permeation. These results indicate that the formulation containing 10% of oleic acid with 10% isopropyl myristate give better penetration of heparin sodium through rat skin.