Terbinafine hydrochloride loaded nanoemulsion based gel for topical application

The objective of the present study was to design and develop topical nanoemulsion based Terbinafine HCl (TBH) gel to increase its permeability and efficacy using rat as an animal model. Nanoemulsions were prepared by two different techniques viz. high pressure homogenization and high speed homogenization, the prepared nanoemulsions were incorporated into carbomer gel to obtain nanoemulsion based gel, which designated as Gel-P and Gel-S respectively. The developed gels were evaluated for drug content, stability, spreadability, and in vitro permeation using pork skin. The in vivo antifungal efficacy of the developed gels was assessed in albino Wistar rats. The globule size obtained by high pressure homogenization was less than 2 nm in radius (r.nm) and that by high speed homogenization was less than 10 r.nm. In vitro permeation studies revealed that Gel-P (51.19 ± 0.81 %) had higher permeation when compared to Gel-S (31.72 ± 1.12 %) and marketed cream (19.78 ± 1.01 %) which is essential to treat topical fungal diseases. In vivo antifungal studies in Wistar rats infected with Trichophyton mentagrophytes revealed that topical application of Gel-P and Gel-S cured the infection within 3 days compared to 14 days for Marketed Cream (M.C). This study confirms that the nanoemulsion gels provided greater permeation followed by cure rates of poorly soluble TBH in animal model and hence these systems could be the preferred drug carriers for drugs intended for topical use to overcome the permeability and efficacy problems.