Preparation and characterization of anti-acne ethosomes using cold and thin-layer hydration methods

Objective: This study aimed to prepare and characterize anti-acne ethosomes using the cold- and thin-layer hydration methods. Methods: A sonication step was included during ethosome preparation to improve the quality of the cold method. Azelaic acid, Phospholipon 90G, ethanol, propylene glycol, and phosphate buffer (pH 7.4) were used in the procedures. Prepared ethosomal suspensions were characterized using transmission electron microscopy, particle-size analysis, and spectrophotometry. Results: Ethosomes prepared using the thin-layer hydration method (F1) had small unilamellar vesicles, while those prepared using the cold method with 15-min sonication (F4) showed spherical, elliptical, unilamellar, and multilamellar vesicles. F1 ethosomes had a D_mean volume of 648.57±231.26, whereas those prepared using the cold method with 5- (F2), 10- (F3), and 15-min (F4) sonication had D_mean volumes of 2734.04±231.49 nm, 948.90±394.52 nm, and 931.69±471.84 nm, respectively. Polydispersity indices of F2, F3, and F4 ethosomes were 0.74±0.21, 0.86±0.05, and 0.91±0.03, respectively, with a poor particle-size distribution, compared to that of F1 (0.39±0.01). Zeta potentials of F1-F4 ethosomes were -38.27±1.72 mV, -23.53±1.04 mV, -31.4±1.04 mV, and -34.3±1.61 mV, respectively. Entrapment efficiencies of F1-F4 ethosomes were 90.71±0.11%, 53.84±3.16%, 72.56±0.28%, and 75.11±1.42%, respectively. Conclusion: Anti-acne ethosomes produced using the thin-layer hydration method had superior properties than those produced using the cold method with 15-min sonication.