Abstract: The present invention provides a novel cationic lipid, a preparation method of the same and a delivery system comprising the same. The cationic lipid of the present invention is used for the preparation of delivery systems of nucleic acids or physiologically active anionic proteins. The cationic lipid of the present invention can be conveniently prepared and purified by a simple process and is therefore economically highly advantageous for industrial-scale production thereof. Further, a nucleic acid or protein delivery system comprising the cationic lipid of the present invention not only significantly improves the intracellular delivery efficiency of desired nucleic acid drugs (such as DNAs, RNAs, siRNAs, antisense oligonucleotides, and nucleic acid aptamers) or anionic proteins having physiological activity, but also is usefully used to augment therapeutic efficacy of nucleic acid or protein drugs due to attenuated cytotoxicity of the delivery system.

Abstract: The present invention provides a cationic phospholipid liposome composition comprising 1,2-dioleoyl-sn-glycero-S-ethylphosphocholine (EDOPC), 3?-[N—(N?,N?-dimethylaminoethane)-carbamoyl] cholesterol (DC-cholesterol) and 1,2-diphytanoyl-sn-glycero-3-phosphoethanolamine (DPhPE), a liposome-nucleic acid complex which is capable of forming a complex therewith, and a pharmaceutical composition comprising the same. The cationic phospholipid liposome of the present invention is highly effective for intracellular delivery of nucleic acids and reduction of cytotoxicity, as compared to conventional liposome products. Therefore, the present invention can be useful for gene therapy via intracellular delivery of a desired material to target cells.