Nano-based mouthwash containing white basil essential oil a potent alternative for oral hygiene.

Background and Objectives: White basil (Ocimum gratissimum L. Lamiaceae) essential oil exhibits potent antibacterial effects but its aqueous insolubility and high volatility restrict its applications. This study aimed to develop a nanodispersed mouthwash containing white basil essential oil, optimizing of surfactant/co-surfactant type and ratio, assess its physicochemical stability and antibacterial efficacy against Streptococcus mutans ATCC 25175. Materials and Methods: Formulations combining white basil essential oil, Tween-80, isopropanol, Labrasol and water were prepared. Particle size, zeta potential, and pH were measured. Stability was evaluated under accelerated (40°C, 75% RH) and stressed (60°C, 75% RH) conditions over three months. Antimicrobial efficacy was assessed via minimum bactericidal concentration (MBC) after 30-second exposure. Results: Characterization of the optimized formulation revealed an average particle size of 128 nm, neutral zeta potential, pH 3.42. Stability testing demonstrated thermodynamic resistance under all storage conditions for three months without phase separation or significant size change. The MBC against Streptococcus mutans was 0.4% w/v essential oil following 30 seconds of exposure. A corresponding mouthwash with 0.4% w/v essential oil demonstrated equivalent bactericidal activity. Conclusion: Nanodispersion offers a promising strategy for white basil essential oil in mouthwash formulations. The developed formulation shows favorable stability and rapid bactericidal action, supporting further evaluation for clinical and commercial development.