ABSTRACT
OBJECTIVES: Microemulsions are fluid, isotropic, colloidal systems that have been widely studied as drug delivery systems. The percutaneous transport of active agents can be enhanced by their microemulsion formulation when compared to conventional formulations. The purpose of this study was to evaluate naftifine-loaded microemulsions with the objective of improving the skin permeation of the drug. MATERIALS AND METHODS: Microemulsions comprising oleic acid (oil phase), Kolliphor EL or Kolliphor RH40 (surfactant), Transcutol (co-surfactant), and water were prepared and physicochemical characterization was performed. In vitro skin permeation of naftifine from microemulsions was investigated and compared with that of its conventional commercial formulation. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to evaluate the interaction between the microemulsions and the stratum corneum lipids. Candida albicans American Type Culture Collection (ATCC) 10231 and Candida parapsilosis were used to evaluate the antifungal susceptibility of the naftifine-loaded microemulsions. RESULTS: The microemulsion formulation containing Kolliphor RH40 as co-surfactant increased naftifine permeation through pig skin significantly when compared with the commercial topical formulation (p<0.05). ATR-FTIR spectroscopy showed that microemulsions increased the fluidity of the stratum corneum lipid bilayers. Drug-loaded microemulsions possessed superior antifungal activity against Candida albicans ATCC 10231 and Candida parapsilosis. CONCLUSION: This study demonstrated that microemulsions could be suggested as an alternative topical carrier with potential for enhanced skin delivery of naftifine.
ABSTRACT
Acne vulgaris is the chronical, multifactorial and complex disease of the pilosebaceous unit in the skin. The main goal of the topical therapy in acne is to target the drug to epidermal and deep dermal regions by minimizing systemic absorption . Isotretinoin, a retinoic acid derivative, is the most effective drug in acne pathogenesis. Because systemic treatment may cause many side effects, topical isotretinoin treatment is an option in the management of acne. However, due to its high lipophilic character, isotretinoin tends to accumulate in the upper stratum corneum, thus its penetration into the lower layers is limited, which restricts the efficiency of topical treatment. Microemulsions are fluid, isotropic, colloidal drug carriers that have been widely studied as drug delivery systems. The percutaneous transport of active agents can be enhanced by microemulsions when compared with their conventional formulations. The purpose of this study was to evaluate microemulsions as alternative topical carriers for isotretinoin with an objective to improve its skin uptake. After in vitro permeation studies, the dermal penetration of isotretinoin from microemulsions was investigated by tape stripping procedure. Confocal laser scanning microscopy provided insight about the localization of the drug in the skin. The interaction between the microemulsion components and stratum corneum lipids is studied by ATR-FTIR spectroscopy. The relative safety of the microemulsions was assessed in mouse embryonic fibroblasts using MTT viability test. The results indicate that microemulsion-based novel colloidal carriers have a potential for enhanced skin delivery and localization of isotretinoin.
