Development of liposomal formulation for green tea catechins targeted for the treatment of vaginal inflammation

Abstract

Green tea catechins are well known for their antioxidative and anti-inflammatory properties. In this connection, catechins are thought to be potential candidates in prevention and treatment of diseases caused by oxidative damage. In addition, catechins have been shown to be effective in the treatment of genital warts. However, they exhibit low bioavailability and poor solubility, which limits their use. This project focused on development of liposomal delivery system containing catechin and epicatechin, respectively, as mean to circumvent their physiochemical limitations and to enhance their biological activity. The formulation was intended for treatment of genital warts/vaginal inflammation. To become closer to an actual in vivo application, drug-bearing liposomes were incorporated in a mucoadhesive hydrogel. The optimized liposomal formulation for catechin was sonicated for 2 minutes and had an average diameter of 150 nm. These vesicles entrapped approximately 50 % of catechin. The corresponding liposomes prepared with epicatechin were found to have smaller size, however the entrapment was similar. Liposomes containing catechin were further incorporated in a hydrogel vehicle and the hydrogel was found to exhibit satisfactory adhesiveness and cohesiveness. In vitro release of catechin from liposomal preparations (both in a form of suspension and incorporated in hydrogel) was performed on Franz diffusion cells under condition simulating both the vaginal environment and physiological conditions. Liposomal hydrogels were found to provide sustained release of catechin. In conclusion, we can confirm that encapsulation of catechins in liposomes and their subsequent incorporation in hydrogels provides potentials for development of novel drug delivery systems for vaginal therapy with catechin.