Skin pretreatment with lasers promotes the transdermal delivery of vitamin C derivatives

The objective of this study is to investigate the effects of two lasers (erbium:YAG and CO₂) on the ability to enhance skin permeation of two vitamin C derivatives, 3-O-ethyl ascorbic acid (EAC) and ascorbic acid 2-glucoside (AA2G). The study was taken in the skin of a female nude mouse (Balb/c-nu strain, 8 weeks old) in vitro. The histologic and ultrastructural changes of the nude mouse skin treated by the lasers were examined under light microscopy and transmission electron microscopy, respectively. The in vitro permeation of vitamin C derivatives was performed in Franz cell. The stratum corneum (SC) layer in the skin was partly ablated by erbium:YAG laser treatment, resulting in greater permeation of both vitamin C derivatives. The flux of EAC and AA2G across erbium:YAG laser-treated skin was 105 to 189-fold and 35 to 78-fold higher, respectively, than their flux across intact skin. The increase in enhancement ratio with increase in fluency decreases markedly for both compounds at the last dose escalation (from 5.0 to 6.3 J/cm²). Both SC ablation and a thermal effect may contribute to the effect of the CO₂ laser on skin structure. The flux of EAC and AA2G across CO₂ laser-treated skin was 181 to 277-fold and 82 to 117-fold higher, respectively, than their flux across intact skin. We concluded that both erbium:YAG and CO₂ laser pretreatment increased the transdermal flux of two stable vitamin C derivatives, EAC and AA2G. The optimal fluency for the Er:YAG laser was 5 J/cm².