Purpose: The aim of this study was to formulate nano-emulsions comprising natural oils and the active pharmaceutical ingredients (APIs) clofazimine (CLF), artemisone (ATM) and decoquinate (DQ) in order to determine effectiveness of the nano-emulsions for topical delivery of the APIs. The APIs alone do not possess suitable physicochemical properties for topical drug delivery.
Methods: Nano-emulsions were formulated with olive and safflower oils encapsulating the APIs. Skin diffusion and tape stripping studies were performed. By using the lactate dehydrogenase (LDH) assay, in vitro toxicity studies were carried out on immortalized human keratinocytes (HaCaT) cell line to determine cytotoxicities due to the APIs and the nano-emulsions incorporating the APIs.
Results: The nano-emulsions were effective in delivering the APIs within the stratum corneum-epidermis and the epidermis-dermis, were non-cytotoxic towards HaCaT cell lines (p < 0.05) and inhibited Mycobacterium tuberculosis in vitro.
Conclusion: Natural oil nano-emulsions successfully deliver CLF, ATM and DQ and in principle could be used as supplementary topical treatment of cutaneous tuberculosis (CTB). Graphical Abstract ᅟ.
Keywords: artemisone; clofazimine; cutaneous tuberculosis; decoquinate; nano-emulsions.