Abstract: A solubilizing composition containing (A) at least one oily component selected from esters of oleic acid with alcohols having 1 to 3 carbon atoms and triglycerides of fatty acids having 6 to 12 carbon atoms, (B) a polyoxyethylenesorbitan fatty acid ester, (C) a polyhydric alcohol which is liquid between 15° C. and 25° C., and (D) one or more acidic phospholipids where the fatty acid constituting an acyl group thereof is selected from saturated fatty acids having 6 to 14 carbon atoms and unsaturated fatty acids having 16 to 18 carbon atoms, which contains 20 to 40% by weight of the component (A), 30 to 45% by weight of the component (B), 15 to 40% by weight of the component (C), and 0.5 to 4% by weight of the component (D), based on 100% by weight of a total amount of the components (A) to (D).

Abstract: A phospholipid derivative represented by the following formula (1): wherein [PG]k represents a residue of polyglycerin having a polymerization degree of k, wherein k is 2 to 50, R1CO and R2CO independently represent an acyl group having 8 to 22 carbon atoms, symbol “a” independently represents an integer of 0 to 5, symbol “b” independently represents 0 or 1, M represents hydrogen atom, an alkali metal atom, an ammonium, or an organic ammonium, and k1, k2, and k3 represent numbers satisfying the following conditions: 1?k1?(k+2)/2, 0?k2, and k1+k2+k3=k+2. The phospholipid derivative is highly safe for living bodies and can be suitably utilized in drug delivery systems such as liposome, and the like.

Abstract: A solubilizing composition containing (A) at least one oily component selected from esters of oleic acid with alcohols having 1 to 3 carbon atoms and triglycerides of fatty acids having 6 to 12 carbon atoms, (B) a polyoxyethylenesorbitan fatty acid ester, (C) a polyhydric alcohol which is liquid between 15° C. and 25° C., and (D) one or more acidic phospholipids where the fatty acid constituting an acyl group thereof is selected from saturated fatty acids having 6 to 14 carbon atoms and unsaturated fatty acids having 16 to 18 carbon atoms, which contains 20 to 40% by weight of the component (A), 30 to 45% by weight of the component (B), 15 to 40% by weight of the component (C), and 0.5 to 4% by weight of the component (D), based on 100% by weight of a total amount of the components (A) to (D).

Abstract: A phospholipid derivative represented by the following formula (1): wherein [PG]k represents a residue of polyglycerin having a polymerization degree of k, wherein k is 2 to 50, R1CO and R2CO independently represent an acyl group having 8 to 22 carbon atoms, symbol “a” independently represents an integer of 0 to 5, symbol “b” independently represents 0 or 1, M represents hydrogen atom, an alkali metal atom, an ammonium, or an organic ammonium, and k1, k2, and k3 represent numbers satisfying the following conditions: 1?k1?(k+2)/2, 0?k2, and k1+k2+k3=k+2. The phospholipid derivative is highly safe for living bodies and can be suitably utilized in drug delivery systems such as liposome, and the like.