Hibiscus sabdariffa Linn, or Roselle, is a medicinal plant used extensively in traditional Thai medicine since ancient
times. The extracts of Roselle calyces possess antioxidant activity and have potential for development as active ingredients in
cosmetic products. However, the limitations of using Roselle extracts in cosmetics are its low skin permeation and dermal
irritation. Liposome technology is an obvious approach that might overcome these problems. Liposome formulations of
standardized Roselle extracts were developed with various lipid components. The formulation showing the highest entrapment
efficiency was selected for stability, skin permeation and dermal irritability studies. The liposome formulation with the highest
entrapment efficiency (83%) and smallest particle size (332 mm) was formulated with phosphatidylcholine from soybean
(SPC): Tween 80: deoxycholic acid (DA); 84:16:2.5 weight ratio, total lipid of 200 g/mL and 10% w/v Roselle extract in final
liposomal preparation. This liposome formulation was found to be stable after storage at 4°C, protected from light, for 2
months. The in vitro skin permeation studies, using freshly excised pig skin and modified Franz-diffusion cells, showed that
the liposome formulation was able to considerably increased the rate of permeation of active compounds in Roselle extracts
compared to the Roselle extract solution. The in vivo dermal irritability testing on rabbit skin showed that the liposome
formulation dramatically decreased skin irritability compared to the unformulated extract. These results showed that the
liposomes containing Roselle extracts had good stability, high entrapment efficacy, increased skin permeation and low skin
irritation.

Keywords: Liposome, Antioxidant, Skin irritation, Hibiscus sabdariffa, Roselle