A cationic cholesterol derivative; as a component of lipoplexes with DOPE and mRNA, has been used for transfection of A549 cells without affecting cell viability; incubation of liposomes or lipoplexes with human whole blood has no significant effect on neutrophil elastase or β-thromboglobulin levels or the number of platelets and red and white blood cells, indicating hemocompatibility; has been widely used in the synthesis of liposomes for the delivery of siRNA, DNA, and chemotherapeutic agents into cells and mice