Permeation and distribution of ferulic acid and its alpha-cyclodextrin complex from different formulations in hairless rat skin.

摘要

Ferulic acid (FA) is a natural product that occurs in seeds of many plants where it is generallylocated in the bran. This compound is a multifunctional ingredient endowed with antioxidative, radicalscavenging, sunscreening and antibacterial actions. The aim of this study was to analyse the ferulic acidcutaneous permeation and distribution, through and into the skin layers, from different cosmetic vehicles,an O/W emulsion (pH 6.0) and two gel-type formulations at different pH levels (6.0 and 7.4), containingFA alone or an inclusion complex with α-cyclodextrin (CD-FA). In vitro permeation studies wereperformed in vertical diffusion cells using hairless rat excised skin. At appropriate intervals of time, theamount of permeated sunscreen/radical scavenger was evaluated by high-performance liquid chromatography(HPLC). At the end of experiments, treated skin samples were sectioned with a cryomicrotomeand the FA content of the individual slices was analysed by HPLC. FA-containing formulations, O/Wemulsion, gels A and B, originated FA fluxes of 8.48±2.31, 8.38±0.89 and 5.72±0.50 μg/cm2 h,respectively, thus suggesting the pH influence on FA percutaneous permeation. The use of the inclusioncomplex, CD-FA, determined in all cases a decrease of FA transdermal permeation while no influence ofpH was observed. Gel-type formulations containing FA ensured higher sunscreen storage in thesuperficial layers if compared with O/W emulsion. When FA was included in α-cyclodextrin, FA amountretained into skin layers decreased markedly.