Lavandula angustifolia Mill. esansiyel yağı yüklü mikroemülsiyon sistemlerinin tasarımı: faz davranışının haritalanması, fizikokimyasal karakterizasyon ve mikrobiyolojik uygunluk değerlendirmesi

Aim:This study aims to develop and characterize thermodynamically stable microemulsion systems based on Cremophor RH40 and propylene glycol/ethanol in order to overcome the solubility and stability problems of Lavandula angustifolia essential oil obtained from the Isparta region. [1–3,10–12]Methods:Pseudo-ternary phase diagrams were constructed by aqueous titration to determine the optimum compositions. The formulations were characterized in terms of droplet size (DLS), polydispersity index, zeta potential, viscosity, and thermal behavior by differential scanning calorimetry (DSC), while microbiological efficacy was evaluated according to the ISO 11930 protocol. [10–12,17]Results:Analyses showed that the widest isotropic microemulsion regions were obtained at Smix ratios of 2:1 and 3:1. The optimized systems exhibited droplet sizes in the range of 100–140 nm, polydispersity indices below 0.25, and zeta potential values between −14 and −18 mV. In addition to viscosity values of 0.6–1.5 Pa·s, which are ideal for topical application, preservative-free formulations provided >3 log reduction in bacterial count by day 7 and showed no phase separation during 8-week stress testing. [10–14,17,18]Conclusion:It was demonstrated that the developed nanocarrier system successfully encapsulates lavender essential oil while maintaining its physical stability. The self-preserving character and high solubilization capacity of the system offer a safe and effective model for pharmaceutical and cosmetic industries. [1–3,10–14,17,19]