NANOEMULSION OF CHAMPACA FLOWER (MAGNOLIA ALBA) OIL AS AN ANTIBACTERIAL CANDIDATE: OPTIMIZATION, CHARACTERIZATION, AND THERMODYNAMIC STABILITY TESTING

Objective: This study aims to investigate the antibacterial potential of Magnolia alba (M. alba) essential oil and to optimize the composition of the oil, surfactant mix, and distilled water in order to formulate a stable topical nanoemulsion of M. alba. The focus is on enhancing the thermodynamic stability and achieving a small particle size of the nanoemulsions. Methods: The chemical composition of champaca oil was analyzed using Gas Chromatography-Mass Spectrometry (GC-MS), and its antibacterial activity against Staphylococcus aureus was evaluated through a dilution test, with ciprofloxacin serving as the positive control. The nanoemulsion was optimized using the Simplex Lattice Design (SLD) method in Design Expert 13.0, employing Virgin Coconut Oil (VCO) as the oil phase, Tween 80 as the surfactant, PEG 400 as the co-surfactant, and distilled water as the aqueous phase. We selected the optimal formula based on pH and transmittance values. The optimized nanoemulsion was further characterized for droplet size, zeta potential, and polydispersity index and was subjected to thermodynamic stability tests. Results: M. alba oil contains cyclopentaneacetic acid, 3-oxo-2-pentyl-, methyl ester (15.83%), benzyl alcohol (6.89%), phenyl ethyl alcohol (5.72%), and linalool (4.31%), with a Minimum Inhibitory Concentration (MIC) of 2%. The optimized nanoemulsion formulation, comprising of 4% oil phase, 27% surfactant mix (Smix), and 69% aqueous phase, was clear and stable, with a pH of 5.33, a transmittance of 98.69%, a droplet size of 30.55 nm, a zeta potential of 1.21 mV, and a polydispersity index of 0.026. Conclusion: M. alba oil exhibits promising antibacterial properties against Staphylococcus aureus. The optimized nanoemulsion formulation achieves thermodynamic stability and small droplet size, making it a potential candidate for topical antibacterial applications. Further investigations are required to assess long-term stability.