The Effect of different emulsifiers on the release characteristic of main component of tea tree oil gel formulstions

Abstract

The release characteristic of terpinen-4-ol, the main component of tea tree oil, in gel formulations was investigated. The studied gels were prepared with four different emulsifiers, namely, sorbitan monolaurate, polysorbate 20, polyoxyethylene-10-oleyl-ether, and polysorbate 80 at varying concentrations of 0.5%, 1% and 2%. The tea tree oil content in each formulation was kept constant at 1%. Franz diffusion cell with ethanol as the solvent in the receptor compartment and shed snake skin as a model membrane was used in conducting the release experiment. The amount of terpinen-4-ol from tea tree oil in hydrogels that penetrated the studied skin into the receptor compartment was monitored by gas chromatography. The results showed that tea tree oil gel with 1% polysorbate 20 is the best formulation able to release terpinen-4-ol consistently in every hour. This is likely due to the high hydrophile-lipophile balance (HLB) of poysorbate 20. The surfactant thus may interact with alcohol group in terpinen-4-ol structure resulting in an acceptable hydrogel with best release.