Formulation and Evaluation of a Nano Herbal Gel Incorporating Plant Extracts and Amoxicillin for the Treatment of Bacterial Infections

Background: Bacterial infections remain a major cause of morbidity and mortality, and the rise of antibiotic resistance limits the usefulness of established agents such as amoxicillin. Combining an antibiotic with a plant-derived antibacterial in a topical nanoscale gel may improve local delivery and antibacterial performance. Objective: To formulate and evaluate a Carbopol 940-based nano herbal gel containing Hibiscus rosa-sinensis L. leaf extract and amoxicillin for topical treatment of bacterial infections. Methods: The leaf extract was characterised by ultraviolet–visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and phytochemical screening, and amoxicillin was characterised by FTIR. Six batches (Batch 1–Batch 6) were prepared with varying proportions of extract, amoxicillin, Carbopol 940, glycerin and triethanolamine. The batches were evaluated for particle size, zeta potential, drug loading, encapsulation efficiency, in-vitro drug release, initial physicochemical characteristics (appearance, pH, viscosity and spreadability) and antibacterial activity by the agar well diffusion method.