OPTIMIZATION OF HIGH PRESSURE HOMOGENIZATION IN THE PRODUCTION OF LIPOSOMAL DISPERSIONS

Liposomes are spherical, biodegradable, and biocompatible vesicular systems. These vesicles are built from phospholipid double layers (membranes) surrounding the inner water phase. Liposomes are highly desirable as drug carriers because they can incorporate hydrophilic, hydrophobic and amphipathic drug substances (drugs). The physicochemical properties of liposomes such as size, charge, surface properties and encapsulation efficiency can highly influence their in vivo stability and kinetics. The aim of our study was to prepare liposomal dispersions and to determine the influence of cycles of high pressure homogenization on some parameters, such as vesicle size and polydispersity index (PDI). Higher homogenization pressures and repeated recirculation led to further reduction in vesicle diameter and heterogeneity. For preparing liposomal dispersions Phosal IP 40 and Phosal 75 SA were used (Lipoid, Germany). Liposomal dispersions were prepared according to the thin film hydration method. By sampling after each cycle, an estimate was made of how many cycles are needed for the dispersion to have satisfactory parameters (size and PDI). The size and PDI analysis of the liposomes were carried out by using Zetasizer (Nano series) ZS 90, Malvern Instruments. . High pressure homogenization was carried out in 10 cycles and based on the obtained liposome size values and PDI, was determined how many cycles are needed in the process of homogenization. With each cycle, the size of the liposomes decreased and PDI value was reduced. It has been observed that after 5 cycles of homogenization there is no significant decrease in the size of the liposomes and PDI. Therefore, in the further production of liposomes with active substances with these raw materials, is recommended to use only 5 cycles of homogenization