Photo-responsive release of ascorbic acid and catalase in CDBA-liposome for commercial application as a sunscreen cosmetic

Abstract

Long-term exposure of the skin to UV light causes degenerative effects, which can be minimized by using antioxidant formulations. A remedy is that L-ascorbic acid (Vc) can be applied in commercial sunscreen cosmetics. This study was designed to determine whether 4-cholesterocarbonyl-4′-(N,N'-diethylaminobutyloxy)azobenzene (CDBA) liposome can undergo photoisomerization, and lead to release of ascorbic acid in CDBA-liposome under UV irradiation. Using the standard sonication method, Vc or catalase loaded liposomes containing CDBA were prepared. Size distribution of the liposome, photoisomerization of CDBA either in chloroform solution or in CDBA-liposome, stability of Vc or catalase, the release of Vc from Vc-loaded CDBA-liposome, and the protecting efficacy of CDBA-liposome upon UV irradiation were studied. The results showed that the average diameter of CDBA-liposome was 140 nm. CDBA both in solution and in liposome can undergo trans-to-cis isomerization upon UV irradiation and cis-to-trans isomerization by incubation at 37 °C. Furthermore, both Vc and catalase in CDBA-liposome were much more stable than in their free states, and the release of L-ascorbic acid from CDBA-liposome was photoresponsive. Meanwhile, it was confirmed by in vivo tests that the CDBA-liposome showed a good protecting efficacy from UV irradiation, which implies that this formulation could be used in commercial sunscreen cosmetics.