Development of phospholipid vesicle-based permeation assay models capable of evaluating percutaneous penetration enhancing effect.

OBJECTIVES: The phospholipid vesicle-based permeation assay (PVPA) model has recently been introduced as an in vitro model which can mimic stratum corneum (SC) barriers to estimate the skin permeability of drugs. The aim of this study was to evaluate whether the PVPA model was suitable for the evaluation of penetration enhancing effect of skin penetration enhancers (PE). METHODS: The PVPA model was optimized by changing the lipid composition of both small liposomes (SL), and large liposomes (LL). The barrier properties of the PVPA model were monitored by electrical resistance and permeability measurement of the fluorescent marker Rhodamine B (RB). Then the permeation studies of the five active compounds with different physicochemical properties, namely, ferulic acid, paeoniflorin, albiflorin, tetrahydrocolumbamine, and tetrahydropalmatine, were performed directly on PVPA model to evaluate the penetration enhancing effect of menthol. RESULTS AND DISCUSSIONS: The enhancement ratio (ER) ranking of the five active compounds observed using the optimized PVPA model was in accordance with what observed with Franz diffusion cell device using porcine ear skin. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis of PVPA model and porcine ear skin after treatment with menthol has shown similar mechanism of menthol which perturbs the SC lipid arrangement and extracts the SC lipids. CONCLUSIONS: In summary, the optimized PVPA model was used for the first time for the evaluation of the permeation enhancing effect. The optimized PVPA model has shown potential to be applied in a more standardized, cheaper, and ethical way for the screening of PE.