Arginine based cationic surfactants interaction with stratum corneum model membranes

HERMET, M.; FAIT, M.E.; ZULUETA DÍAZ, Y.M.; MORCELLE, S.R.; BAKÁS, L.; FANANI, M.L.

Congreso; XLIX Reunión Anual SAB; 2021

SAB

Skin delivery’s efficiency is seriously restricted due to the barrier function of the stratum corneum (SC). Surfactants represent one of the most employed chemical permeation enhancers (CPE) used to overcome this issue.Nα-benzoyl-L-arginine decyl- and dodecylamide (C10 and C12) are cationic surfactants we have obtained through means of a biocatalytic strategy. The present work reports their surface activity and their interaction with a quaternary lipid membrane model (SCM), which resembles the SC structure and barrier capacity. Lipid monolayers were used to mimic the simplest unit layer of the SC. We further explored the in-plane structure and elasticity of the SCM-enhancer systems at macro-, micro- and nanoscopic scales. Oleic (OA) and stearic acid (SA) were used as positive and negative CPE controls, respectively.Experiments revealed that C10 and C12 were able to modify the lipid film’s elasticity, dropping the Cs-1 value of SCM up to 30 and 15-20% for C10 and C12 respectively, and showing a dose-dependence effect, stronger than that of OA. They were able to insert themselves into highly packed preformed monolayers, up to an initial surface pressure () of 43−45 mN/m. Cut off values for OA and SA were significantly lower.Direct observation of the films by BAM showed that the addition of 35 mol% of C10 or C12 stabilized liquid-liquid phase separation at lower , probably due to the surfactants’ immiscibility with the most hydrophobic components of the SCM. Notably, this was not the case for SCM films containing OA, which showed an even surface at low .We finally analyzed the lateral structure of the films at nanoscale by means of AFM. The incorporation of the amphiphiles to the SCM changed the domain shape, as rounded-border structures appeared. The presence of C12 and OA did not alter the phase equilibrium, whereas C10 and SA increased the thick phase area coverage by 32 and 69%, respectively.Evidenced collected in these assays suggests both C10 and C12 could be employed as CPE.