Abstract

This study aims to develop sophisticated mathematical models to describe the behavior of a Bergamot oil (BO) nanoemulgel formulation and optimize its physicochemical and biological properties. Conducted in a controlled laboratory setting, the formulation parameters were optimized using a central composite design as part of a response surface methodology approach. The interactions between Tween 80 concentration and homogenization time were explored to achieve an ideal nanoemulsion. Differential scanning calorimetry and attenuated total reflectance-Fourier transform infrared analyses confirmed the successful encapsulation of BO and evaluated its thermal stability. Statistical evaluations through regression modeling and ANOVA indicated significant effects of formulation variables on particle size and zeta potential. The optimized nanoemulgel exhibited a particle size of 116.60 nm, a polydispersity index of 18.9%, and a zeta potential of −26.9 mV, with a high desirability score of 0.938. Kinetic stability studies demonstrated excellent thermodynamic resilience with no signs of phase separation. The antibacterial activity of the optimized BO nanoemulgel showed prominent zones of inhibition, measuring 23.9 ± 0.5 mm against Staphylococcus aureus [Microbial Type Culture Collection and Gene Bank (MTCC) 737], 22.98 ± 0.4 mm against Pseudomonas aeruginosa (MTCC 1035), 21.6 ± 0.3 mm against Bacillus subtilis (MTCC 441), and 20.1 ± 0.2 mm against Escherichia coli (MTCC 443), suggesting broad-spectrum antimicrobial potential. These findings reinforce the utility of BO nanoemulgel as a promising candidate for applications in pharmaceutical and personal care formulations, offering both enhanced drug delivery and effective antibacterial performance.

Key words: bergamot oil, response surface methodology, central composite design, nanoemulgel, antibacterial activity.