Development and Evaluation of Khellin-loaded Microemulgel for Dermatological Applications

Abstract

Microemulsions are optically nanosized emulsions, isotropic and thermodynamically stable. They represent versatile drug delivery systems with high potential because can be administered through all routes. In the present study, we report on the formulation of a microemulsion made with glycerol (2.25%), Labrasol (20.25%) vitamin E acetate (2.50%), and water (75.00%), which was developed using the pseudo-ternary phase diagram. Globules of the microemulsion had PdI less than 0.25 and size of about 17 nm, evaluated by DLS analysis. These values did not change after loading khellin, a natural lipophilic molecules with interesting biological activities, used as a model of lipophilic drug. Carboxymethyl cellulose was selected as gelling polymer to obtain a microemulgel. Viscosity was 22,100.0±1555.6 mPas·s at 21±2°C, while it was 8,916.5±118.1 mPas·s at 35±2°C, remaining stable over time. Khellin recovery was 93.16±4.39% and it was unchanged after 4 weeks of storage (93.23±2.14%). The pH was 6.59±0.19 and it was found 6.42±0.34 at the end of the storage lifetime. The diffusion of khellin from the developed formulation was prolonged over an extended period. Based on overall results and due to the dermatological properties of the ingredients of the formulation, the developed microemulgel loaded with khellin is very promising and suitable for skin care applications.