Ex vivo and skin permeation studies

An ex vivo study has been carried out to simulate the in vivo permeation conditions. Abdominal skin was obtained via abdominal incision from euthanised rats collected from an approved laboratory off site. The skin was immediately placed into ice-cold, bubbled (carbogen, 95:5 O₂/CO₂) cold saline. The elastic liposomal gel equivalent to 1 mL of optimized SUVs was applied to the epidermal surface of an albino rat abdominal skin in a vertical Franz diffusion cell. The other side of the abdominal skin was in contact with the dissolution medium. The entire dissolution assembly was placed on a magnetic stirrer at 37°C±0.5°C and was agitated at 100 rpm. The effective permeation area of the donor cell exposed to the receptor cell was 3.14 cm², and the dissolution medium was 100 mL of PBS at a pH of 6.4. Aliquots (5 mL) of the dissolution medium were withdrawn from the sampling port at different time intervals (5, 10, 15, 30, 45, 60, 120, 240, 480, 720, and 1,440 minutes). Whenever the sample was withdrawn, equal volumes of fresh dissolution medium was added to the beaker to maintain a constant volume. Drug concentrations in the dissolution medium were determined by a UV spectrophotometer at 271 nm. All the experiments were carried out in triplicate and the results were expressed as the mean ± standard deviation.20–27