Effect of preparation methods on the properties of Zataria Multiflora Boiss. essential oil loaded nanoliposomes: characterization of size, encapsulation efficiency and stability

Background: Essential oil (EO) of Zataria multiflora Bioss., contains components with antibacterial and antifungal properties that can be used as substitutes for synthetic drugs and food preservatives. These applications require appropriate carriers like nanoliposome. The purpose of this study was to encapsulate this EO into nanoliposomes. In addition, the effects of preparation methods were evaluated on the physical properties of nanoliposomes. Methods: The EO was encapsulated into nanoliposomes by three different methods including thin film evaporation, ethanol injection and sonication methods. Formation of liposomes and their physical properties was studied by means of particle size, polydispersity index, zeta potential and encapsulation efficiency. In addition the changes in EO retention and mean size distribution were studied during one month of storage at 4±1°C. Results: Liposomal systems prepared by sonication method with about 99 nm displayed the smallest mean size and better dispersivity. The encapsulation efficiency of nanoliposomes containing EO was in the following rank order: thin film evaporation > Ethanol Injection > sonication. Moreover, MLV (multilamellar vesicles) liposomes prepared by the thin layer evaporation method showed better stability during storage. Conclusions: This study indicated that the preparation method can affect the formation of liposomes and their physical properties and storage stability.