CDBA-liposome as an effective sunscreen with longer UV protection and longer shelf life.

Harmful effects caused by the absorption of ultraviolet (UV) light can be reduced by using sunscreens. The long-wavelength UV (UVA) and short-wavelength UV (UVB) protective effects of an azobenzene compound, 4-cholesterocarbonyl-4'-(N,N'-diethylaminobutyloxy) azobenzene (CDBA) liposomal formulation, especially its repeated photo-isomerization were evaluated in the presence of substrates such as propylene glycol and glycerol. It was indicated that periodic UV and visible light irradiation did not affect the photo-isomerization and the structure of CDBA-liposome. The stability and photo-isomerization of CDBA-liposomes were not affected by coexistence of 5% propylene glycol and 5% glycerol. CDBA-liposomes could still perform photo-controlled release of encapsulated active component when mixed with propylene glycol. Moreover, the CDBA-liposome mixed with the cream substrate showed protective function for both UVA and UVB in vitro. The in vivo tests using nude mouse confirmed that the CDBA-liposome could provide a good UV protective efficacy with longer shelf life. Therefore, CDBA-liposomes have the potential using as a new type of commercial sunscreen.