Development and evaluation of ultra-small nanostructured lipid carriers: novel topical delivery system for athlete's foot

Athlete's foot is a fungal infection of the foot which causes dry, itchy, flaky condition of the skin caused by Trichophyton species. In this study, the potential of ultrasmall nanostructured lipid carrier (usNLC)-based topical gel of miconazole nitrate for the treatment of athlete's foot was evaluated. Nanostructure lipid carriers (NLCs) prepared by melt emulsification and sonication technique were characterized for particle size, drug entrapment, zeta potential and drug release. The optimized usNLC revealed particle size 53.79 nm, entrapment efficiency 86.77 %, zeta potential -12.9 mV and polydispersity index (PDI) of 0.27. The drug release studies of usNLC showed initial fast release followed by sustained release with 91.99 % drug released in 24 h. Optimized usNLCs were incorporated into carbopol-934 gel and evaluated for pH (6.8), viscosity (36,400 mPa s) and texture analysis. Antifungal activity against Trichophyton mentagrophytes exhibited wider zone of inhibition, 6.6 +/- 1.5 mm for optimized usNLC3 gel viz-a-viz marketed gel formulation (3.7 +/- 1.2 mm). Hen's egg test-chorioallantoic membrane (HET-CAM) irritation test confirmed optimized usNLC gel to be non-irritant to chorioallantoic membrane. Improved dermal delivery of miconazole by usNLC gel could be achieved for treatment of athlete's foot.