Enhancement of Dermal Delivery of Finasteride Using MicroemulsionSystems

Finasteride is a pharmaceutical agent that treats hair loss and acne with hormonalpatterns. Due to its poor water solubility, and the smaller surface area in comparison to totalskin surface area, penetration of the drug into hair follicles and skin is low. The aim of thisresearch was to formulate, characterize and evaluate in vitro skin permeability of finasteridemicroemulsions (MEs).

Finasteride MEs were prepared using a pseudo-ternary phase diagram method withan appropriate ratio of oil mixture, surfactant-co-surfactant mixture and water. MEs containing1% finasteride were prepared with a suitable amount of oily phase and surfactant and cosurfactant.The physicochemical properties of these MEs and in vitro skin permeability of MEswere evaluated.

The results showed that the mean droplet size range of ME samples was 5–17 nm andpH was 5.1–5.7. The viscosity of MEs ranged from 86.4–209.6 cps. The drug release profileshowed that 49.510% of the drug was released (ME-F-6) over the 24 hours of the experiment.The kinetics of drug release from all selected MEs were approximately described by Higuchiand first-order modeling. All ME formulations with different compositions and propertiessignificantly increased flux and permeability coefficient from rat skin. The selected MEs exhibit99.9% finasteride after six months of storage.

This study showed that any change in the content and composition of MEs couldchange the physical and chemical properties in addition to ME permeability parameters. TheMEs increased permeability of the skin to finasteride.