Fabrication of Highly Deformable Bilosomes for Enhancing the Topical Delivery of Terconazole: In Vitro Characterization, Microbiological Evaluation, and In Vivo Skin Deposition Study

The current study aimed to load terconazole (TCZ), an antifungal agent with low permeability characteristics, into highly deformable bilosomes (HBs) for augmenting its topical delivery. HBs contain edge activator in addition to the constituents of traditional bilosomes (Span 60, cholesterol, and bile salts). More elasticity is provided to the membrane of vesicles by the existence of edge activator and is expected to increase the topical permeation of TCZ. HBs were formulated using ethanol injection technique based on 2(4) complete factorial design to inspect the impact of various formulation variables (bile salt type and amount, edge activator type, and sonication time) on HBs characteristics (entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP)). The optimum formula (HB14) was decided based on Design-Expert((R)) software and was utilized for further explorations. HB14 exhibited EE%=84.25 +/- 0.49%, PS=400.10 +/- 1.69 nm, PDI=0.23 +/- 0.01, and ZP=-56.20 +/- 0.00 mV. HB14 showed spherical vesicles with higher deformability index (9.94 +/- 1.91 g) compared to traditional bilosomal formula (3.49 +/- 0.49 g). Furthermore, HB14 showed superior inhibition of Candida albicans growth relative to TCZ suspension using XTT (2,3-bis(2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay. Moreover, in vivo skin deposition studies revealed superior TCZ deposition inside the skin from HB14 compared to traditional bilosomal formula and TCZ suspension. Moreover, histopathological examination in rats assured the safety of HB14 for topical use. Concisely, the obtained outcomes confirmed the pronounced efficacy of HBs for topical delivery of TCZ.

Automated summary

The study successfully loaded the antifungal drug terconazole (TCZ) into highly deformable bilosomes (HBs) to enhance its topical delivery. The optimized HB14 formula exhibited excellent entrapment efficiency, particle size, and zeta potential, with superior inhibition of Candida albicans growth. In vivo skin deposition studies showed enhanced TCZ deposition from HB14 compared to traditional bilosomal formulas, confirming the efficacy of HBs for topical delivery of TCZ.