Design and characterization of banana pseudostem-derived cellulose nanofibrous gel for topical delivery of ketoconazole.

Cellulose nanofibers (CNFs) were extracted from banana pseudostem using an alkali acid hydrolysis method and evaluated for their potential application in topical drug delivery. Compositional analysis confirmed a high cellulose content (94.13 ± 2.12%) with minimal hemicellulose (4.15 ± 3.21%) and lignin (0.71 ± 0.54%). Dynamic light scattering revealed a particle size of 240.8 nm, PDI of 0.341, and a zeta potential of -29 mV, while scanning and transmission electron microscopy demonstrated nanoscale dimensions (~55 nm diameter) with high crystallinity and thermal stability. The aqueous dispersion of extracted CNFs and Carbopol 934P were mixed with ketoconazole solution to form ketoconazole-loaded nanofibrous gel system. The formulation was optimized using a two-factor, three-level central composite design, yielding an optimized composition of 1% w/v CNFs, 0.5% w/v Carbopol 934P, and 2% w/v ketoconazole. The optimized nanogel exhibited neutral pH, high viscosity, excellent spreadability, thermal stability, and an amorphous drug dispersion. In vitro release showed 99.70% ketoconazole release, while ex vivo permeation studies demonstrated enhanced skin diffusion (42.31 ± 1.74%) within 360 min. The formulation displayed significant antibacterial activity against S. aureus and E. coli and antifungal activity against Candida albicans (23.0 ± 0.2 mm inhibition zone). Biocompatibility assessment using Vero cells and histopathological evaluation confirmed non-cytotoxicity and absence of skin irritation respectively. This study provides new insight into the valorization of banana pseudostem agro-waste as a sustainable and stable nanofibrous carrier, addressing critical gaps in eco-friendly, effective, and safe topical antifungal drug delivery systems.