Background: Overcoming the skin barrier to achieve the transdermal penetration of drugs across the stratum corneum (SC) remains a significant challenge. Our previous study showed that Fu’s cupping therapy (FCT) contributes to the transdermal enhancement and percutaneous absorption rate of representative drugs and improves their clinical effects. This work was to evaluate the transdermal enhancement effect of FCT on drugs with different molecular weights (MW).
Methods: we investigated the enhancements in the transdermal penetration of eight types of model drugs through the skin from BALB/c-nu mice and Sprague Dawley rats using Franz diffusion devices. In addition, 3% azone, 5% azone, 3% pep-permint oil, and 5% peppermint oil were used as penetration enhancers to study the transdermal behaviour of these drugs.
Results: Our results showed that the BALB/c-nu mouse skin was the best transdermal media, and the optimal time for FCT was 10 min. Compared with other penetration enhancers, FCT exerted a significantly improved effect on enhancing the per-cutaneous penetration of the selected log(P)-model drugs in addition to the two large MW drugs (ginsenoside Rg1 and noto-ginsenoside R1). A statistical analysis revealed that the relationship between the log(P) of various model drugs and the per-meability coefficient [log(Pcm)] of the FCT group was log(Pcm)=0.080(log(P))2-0.136(log(P))-0.282.
Conclusion: FCT may be used as a novel method for enhancing the physical penetration and thus effectively promoting the transdermal absorption of drugs and might lay a foundation for future research on drug transdermal technology.