Enhancing stability of Eucalyptus citriodora essential oil by solid nanoliposomes encapsulation

Eucalyptus citriodora essential oil (ECEO) possesses numerous pharmaceutical properties. However, effective applications of ECEO are limited by their volatile nature and poor stability. For purpose of improving the stability and prolonging the shelf life of ECEO, it was encapsulated in solid nanoliposomes (SLPs) by the thin film dispersion method followed by the freeze-drying process. The optimal concentration of ECEO in liposomes was 4.0 mg/mL, and its particle size was found to be 266.56 nm with PDI of 0.188, the zeta potential of -33.73 mV. The maximum encapsulation efficiency (EE) of ECEO in liposomes was obtained as 22.47%. β-cyclodextrin was used as cryoprotectant during freeze-drying process with the suitable ratio of 6:1 to the lipid. Also, results of FT-IR and QCM confirmed that ECEO was encapsulated in solid liposomes successfully. Meanwhile, the morphological features of ECEO-SLPs were analyzed by AFM. Moreover, the release rate and the storage stability of ECEO-SLPs were also measured, which revealed that ECEO encapsulated in solid liposomes have strong stability and the products of ECEO-SLPs can be extended to relevant industrial applications.