Formulation and evaluation of Argemone mexicana oil-based nano-emulsion using low-energy method and its antimicrobial assessment

Background and objective: Argemone mexicana seed oil is a plant-derived bioactive known for its potent antimicrobial and anti-inflammatory properties. However, its clinical utility is hindered by poor water solubility, high viscosity, and chemical instability. Nano-emulsion technology provides a promising strategy to enhance the bioavailability and stability of such hydrophobic phytoconstituents. This study aimed to formulate and evaluate a stable nano-emulsion of Argemone mexicana oil using a low-energy method and assess its physicochemical properties and antimicrobial potential. Methods: A spontaneous emulsification technique was used for the development of oil-in-water nano-emulsions using Brij 30 as the primary surfactant. Pseudo-ternary phase diagrams were constructed to determine optimal composition ranges. The prepared formulations were characterized for droplet size, zeta potential, morphology (optical microscopy), viscosity, and physical stability. Antimicrobial activity was evaluated using agar well diffusion method against Escherichia coli. Results: The optimized nano-emulsion (AB1) exhibited a mean droplet size of