Transdermal penetration of diclofenac in the presence of AAPH-derived peroxyl radicals

Abstract

In vitro transdermal delivery of diclofenac across pig skin in the presence of AAPH-derived peroxyl radicals (2,2′-azo-bis(2-amidinopropane)dihydrochloride) has been studied. The transdermal absorption of diclofenac was estimated using high-performance liquid chromatography after its incubation in vertical cells. The diclofenac transdermal penetration was highly modified by peroxyl radicals. In the presence of AAPH, lower diclofenac absorption was observed. This effect was inhibited by ferulic acid. This could be explained by diclofenac–peroxyl radical interactions. In the pretreatment skin with AAPH, lower diclofenac absorption was higher than control experiments. This behavior should be considered in the topical administration of pharmaceutical preparations containing diclofenac.

Keywords:

• AAPH
• absorption
• diclofenac
• peroxyl radicals
• transdermal

Acknowledgment

This work was supported by Faculty of Chemistry of Pontificia Universidad Católica de Chile and by FONDECYT (project no. 11060323).

Declaration of interest: The authors report no conflicts of interest.