Formulation and Evaluation of Telmisartan-Loaded Transferosomal Gel for Enhanced Transdermal Delivery

Telmisartan is a medication used to treat high blood pressure, and it belongs to a class of drugs called angiotensin II receptor blockers. However, it has low solubility in water, which can lead to inconsistent absorption when taken by mouth. The study was designed to create and test telmisartan-loaded transferosomes that were added to a Carbopol gel for delivering the drug through the skin. Pre-formulation studies, including the physical appearance, solubility, melting point, and UV spectral analysis, along with drug-excipient compatibility testing using FTIR, were carried out. Five formulations (F1-F5) were made using the reverse phase evaporation method with soya lecithin and either Span 60, Span 80, or Tween 80 as edge activators. They were tested for zeta potential, particle size, entrapment efficiency, surface shape, and percentage yield. The vesicles were added to Carbopol 934P gel, and the gel was tested for pH, how easily it spreads, the amount of drug it contains, its thickness, and how much drug is released in a lab setup using Franz diffusion cells. Formulation F4 had the best overall results: it had a particle size of 158.7 nm, a zeta potential of -31.6 mV, an entrapment efficiency of 89.5%, and a percentage yield of 91.2%. The SEM image showed mostly round-shaped bubbles with smooth outer surfaces. The pH of the F4 gel was 5.91, its spreadability was 8.02 g.cm/s, the drug content was 97.98%, and the viscosity was 2369 cps. It released the slowest and most steady way (55.8% over 6 hours), and the release followed the Korsmeyer-Peppas model with n = 0.74, which shows anomalous (non-Fickian) transport. The use of telmisartan-loaded transferosomal gel is a promising method for achieving sustained and controlled transdermal delivery.