Introduction. Liposomal preparations have a number of advantages: they protect the cells of the body from the toxic effects of drugs; prolong the action of the drug introduced into the body; protect medicinal substances from degradation; contribute to the manifestation of targeted specificity due to selective penetration from the blood into tissues; change the pharmacokinetics of drugs, increasing their pharmacological efficacy; allow you to create a water-soluble form of a number of medicinal substances, thereby increasing their bioavailability.In this work, studies were carried out to develop a methodology for determining the degree of inclusion in liposomes from soy lecithin of cinnarizine, which has found wide application as a corrector of cerebral circulation disorders.Purpose. The purpose of the study is to determine the amount of adsorption of cinnarizine with liposomes from soy lecithin.Materials and methods. Cinnarizine liposomes from soy lecithin were prepared by the hydration/rehydration method. To study the characteristics of the degree of incorporation of cinnarizine into liposomes, the method of equilibrium dialysis was used. The choice of this method is due to the fact that the quantitative analysis of the equilibrium concentration of cinnarizine in the dispersion medium, which is necessary to determine the amount of adsorption, is hampered by the presence of a dispersed phase, liposomes. A semipermeable membrane with a pore diameter sufficient for the penetration of cinnarizine molecules, but impermeable to liposomes, makes it possible to obtain a cinnarizine solution with a concentration close enough to the concentration in the dispersion medium of liposomes. The solution thus obtained can be subjected to quantitative analysis using spectrophotometry.Results. A graph of the dependence of the value of adsorption of cinnarizine on liposomes on the equilibrium concentration was plotted. It was found that the value of adsorption of cinnarizine during the treatment of liposomes with ultrasound is less for all the studied concentrations. At an equilibrium concentration of cinnarizine of more than 0.0003 mol/l, the proportion of the prearat associated with liposomes stabilizes. Without sonication at the level of 24.83 ± 1.15%, with sonication at the level of 18.4 ± 1.20%.Conclusion. It has been established that ultrasonic treatment of liposomes is expedient when cinnarizine is added to a dry lipid film, since it is a factor that increases bioavailability