Clinical application of treprostinil in pulmonary arterial hypertension is hampered by adverse effects caused by its high dosing frequency. The objective of this investigation was to Formulate an adhesive-type transdermal patch of treprostinil and evaluate it both in vitro and in vivo. A 32-factorial design was utilized to optimize the selected independent variables (X1: drug amount, X2: enhancer concentration) on the response variables (Y1: drug release, Y2: transdermal flux). The optimized patch was evaluated for various pharmaceutical properties, skin irritation, and pharmacokinetics in rats. Optimization results signify considerable influence (p < 0.0001) of X1 on both Y1 and Y2, as compared to X2. The optimized patch possesses higher drug content (>95%), suitable surface morphology, and an absence of drug crystallization. FTIR analysis revealed compatibility of the drug with excipients, whereas DSC thermograms indicate that the drug exists as amorphous in the patch. The adhesive properties of the prepared patch confirm adequate adhesion and painless removal, while the skin irritation study confirms its safety. A steady drug release via Fickian diffusion and greater transdermal delivery (~23.26 µg/cm2/h) substantiate the potential of the optimized patch. Transdermal therapy resulted in higher treprostinil absorption (p < 0.0001) and relative bioavailability (237%) when compared to oral administration. Overall, the results indicate that the developed drug in the adhesive patch can effectively deliver treprostinil through the skin and could be a promising treatment option for pulmonary arterial hypertension.
Keywords: optimization; patch; pharmacokinetics; pulmonary arterial hypertension; transdermal; treprostinil.