Two types of biocompatible surfactants were evaluated for
their capability to formulate skin-friendly/non-irritant microemulsions as vehicles for two poorly water-soluble model
drugs differing in properties and concentrations: alkyl
polyglucosides (decyl glucoside and caprylyl/capryl glucoside) and ethoxylated surfactants (glycereth-7-caprylate/
caprate and polysorbate 80). Phase behavior, structural inversion and microemulsion solubilization potential for
sertaconazole nitrate and adapalene were found to be highly
dependent on the surfactants structure and HLB value.
Performed characterization (polarized light microscopy,
pH, electrical conductivity, rheological, FTIR and DSC
measurements) indicated a formulation containing glycereth-7-caprylate/caprate as suitable for incorporation of both
drugs, whereas alkyl polyglucoside-based systems did not
exhibit satisfying solubilization capacity for sertaconazole
nitrate. Further, monitored parameters were strongly affected by sertaconazole nitrate incorporation, while they
remained almost unchanged in adapalene-loaded vehicles.
In addition, results of the in vivo skin performance study
supported acceptable tolerability for all investigated formulations, suggesting selected microemulsions as promising carriers worth exploring further for effective skin delivery of model drugs.