Abstract: A liposome for delivery of nucleic acid is provided herein, comprising cationic lipid compound, a phospholipid and a PEGylated lipid, wherein the cationic lipid compound is in an amount from 50 wt % to 90 wt % and consist of a lipid compound and a cholesterol lipid compound. A nucleic acid liposome formulation comprising the said liposome and the nucleic acid encapsulated by the liposome and the method for preparing the same are provided therein. Increased amount of nucleic acid can be loaded into the nucleic acid liposome formulation as described therein. Thus, at the same dosage, intake of the cationic lipid compound is decreased, thereby decreasing toxicity.

Abstract: The present invention discloses a liposome formulation, its preparation method, and its application in the treatment of diseases caused by abnormal gene expression. The liposome formulation comprises complementary cationic lipid pairs, phospholipids, and long-circulating lipids. The method of preparing the liposome formulation comprises: mixing the complementary cationic lipid pairs with the phospholipid and the long-circulating lipid to generate pre-formed vesicles; and then mixing the pre-formed vesicles with the nucleic acid solution to generate the liposome-nucleic acid formulation. This liposome formulation provided by the present invention is easily prepared; and in the treatment of diseases caused by abnormal gene expression, the liposome formulation can be used to deliver in vivo therapeutic agents, including nucleic acids.