(T1030-06-34) Biogenic Isatin Derivative (TM-19) Loaded Green Silver Nanoparticles Using Citrus Fruit Peel in the Treatment of Fungal Infection: In Vitro and Ex Vivo Studies

Purpose: To develop an environmentally sustainable delivery system for a novel isatin derivative (TM-19) using biogenically synthesized silver nanoparticles (AgNPs) for enhanced treatment of cutaneous fungal infections. The study aimed to exploit the synergistic antifungal activity between TM-19 and the intrinsic antimicrobial properties of AgNPs while minimizing environmental and human toxicity.

Methods: Citrus lemon peel extract, rich in bioactive compounds, was utilized as a reducing, capping, and stabilizing agent for AgNP synthesis. Key process variables (temperature, extract concentration, silver salt concentration, rotation speed, and pH) were identified and optimized using AGREE tools alongside a Quality by Design (QbD) approach implemented through Design Expert software. The optimized placebo formulation was loaded with TM-19 and characterized for physicochemical properties. In vitro antifungal activity against Candida albicans and Aspergillus niger was assessed through minimum inhibitory concentration (MIC) determination. Ex vivo permeation studies were conducted using rat skin in Franz diffusion cells to evaluate dermal delivery efficiency.

Results: The optimized TM-19-loaded AgNP formulation exhibited a particle size of 82 nm, zeta potential of –18.5 mV, and high drug loading efficiency (62%). Morphological analysis confirmed spherical nanoparticles with uniform size distribution. The formulation demonstrated controlled release kinetics with 89.3% drug release within 12 hours. In vitro antifungal studies revealed significantly lower MIC values against both fungal strains compared to the drug suspension, with values of 67 ± 9.5 µg/mL against C. albicans and 110 ± 13.7 µg/mL against A. niger. Ex vivo permeation studies confirmed enhanced dermal penetration and drug deposition in rat skin compared to conventional TM-19 suspension. Environmental sustainability assessment yielded a high score (0.81) using the AGREE evaluation system.

Conclusion: The biogenic synthesis of TM-19-loaded AgNPs using citrus peel extract offers a rapid, cost-effective, and environmentally sustainable approach for developing antifungal formulations. The optimized nanoparticle system significantly enhanced the antifungal efficacy and skin permeation of TM-19, suggesting its potential as a promising therapeutic approach for cutaneous fungal infections with minimal environmental impact and reduced human toxicity risk.