Abstract:Background: Acne vulgaris is a widespread dermatological disorder affecting adolescents and adults globally, often managed by conventional therapies with limitations such as skin irritation, systemic toxicity, and antimicrobial resistance. In recent years, plant-based formulations have gained interest due to their safety, multi-targeted bioactivity, and favorable patient acceptability. However, poor aqueous solubility and limited dermal permeation of phytoconstituents restrict their clinical utility. Nanoemulsion-based delivery systems offer a promising strategy to enhance solubility, skin retention, and bioavailability of herbal extracts.
Aim: This study aimed to develop and optimize a stable polyherbal nanoemulsion gel containing Bertholletia excelsa (Brazil nut) oil and Ilex paraguariensis (Yerba mate) extract for topical acne management using Box-Behnken design and to evaluate its physicochemical, thermodynamic, and in-vitro release properties.
Materials and Methods: Fifteen nanoemulsion formulations were developed and optimized for droplet size and viscosity using high-energy emulsification. Characterization included droplet size analysis, zeta potential, refractive index, viscosity, thermodynamic stability (centrifugation, heating-cooling, and freeze-thaw cycles), and in-vitro drug release in pH 7.4 phosphate buffer. The optimized nanoemulsion was incorporated into a Carbopol-based gel and evaluated for pH, viscosity, swelling index, extrudability, spreadability, and in-vitro release over 12 hours.
Results: The optimized nanoemulsion formulation demonstrated a droplet size of 107.2 nm, zeta potential of -28.65 mV, and a refractive index of 1.3495, indicating good colloidal stability and dermal compatibility. Thermodynamic stress tests confirmed its physical stability. The nanoemulgel exhibited appropriate pH (5.68), viscosity (3482 cps), swelling index (28%), and excellent spreadability and extrudability. In-vitro release studies revealed a sustained and prolonged drug release, achieving 81.21% over 12 hours.
Conclusion: The developed polyherbal nanoemulgel demonstrated promising physicochemical stability, controlled release kinetics, and excellent topical applicability, suggesting its potential as a safe, effective, and patient-friendly alternative for acne treatment.