Аннотация:A novel strategy is described for preparing pH-sensitive liposomes which releases the encapsulated drug inresponse to the change in pH of surrounding solution. The liposomes, composed of conventional zwitter-ionicegg yolk lecithin (EL), additionally contains a pH-sensitive“activator”(AMS), a derivative of lithocholic acidwith anionic and cationic groups attached to the opposite ends of the steroid core. AMS changes its orientation inthe liposomal membrane thus adapting to acidity/basicity of the outer solution. The rotation of AMS inducesdisordering of the membrane and a fast release of the bioactive cargo. In particular, 50–60 % of the encapsulatedantitumor drug, doxorubicin and cisplatin, leaks from the liposomes within thefirst minute after acidification ofthe surrounding solution. Low-toxic EL-AMS liposomes, loaded with doxorubicin, show themselves active to-wards multidrug resistant cells. Fast-acting and low-toxic EL-AMS liposomes can be used in the design of smartliposomal containers in the drug deliveryfield.