Described are compounds of formula II, formula III, formula IV, and formula V. The compounds of formula II are those wherein R 1 and R 2 are both linear alkyl of 1 to 12 carbons, alkenyl or alkynyl of 2 to 12 carbons； Both of L <； 1>； and L <； 2 >； are linear alkylene or alkenylene consisting of 5 to 18 carbons, or together with N form a heterocycle； X is S； L 3 is a bond or linear alkylene of 1 to 6 carbons, or forms a heterocycle together with N； R 3 is a linear or branched alkylene of 1 to 6 carbons； R 4 and R 5 are the same or different and each is a hydrogen or a compound consisting of linear or branched alkyl of 1 to 6 carbons. Compounds of formula III and formula IV are characterized in that R <； 1 >； is a branched alkyl having 12 to 20 carbons； R <； 2 >； is linear alkyl having 5 to 10 carbons or branched alkyl having 12 to 20 carbons； Each of L 1 and L 2 is a bond or a linear alkyl having 1 to 3 carbon atoms； X is S or O； L <； 3 >； is a bond or lower alkyl； R <； 3 >； is lower alkyl； R 4 and R 5 are the same or different and each is composed of a compound consisting of lower alkyl. The compounds of formula V are those wherein R <； 1 >； is linear or branched alkyl of from 1 to 18 carbons, alkenyl or alkynyl of from 2 to 12 carbons, or cholesteryl； R <； 2>； is 606338680 v1 linear or branched alkyl or alkenyl having 1 to 18 carbons； L 1 is linear alkyl of 5 to 9 carbons, or, when R 1 is cholesteryl, L 1 is linear alkylene or alkenyl of 3 to 4 carbons； X 1 is -O- (CO) - or - (CO) -O-； X <； 2 >； is S or O； La is a bond or linear alkylene of 1 to 6 carbons； R 3 is a linear or branched alkylene having 1 to 6 carbons； R 4 and R 5 are the same or different and each is composed of a compound consisting of linear or branched alkyl of 1 to 6 carbons. The compounds of formula (II), (III), (IV) and (V) may include a pharmaceutically acceptable salt thereof.기술된 것은 화학식 II, 화학식 III, 화학식 IV, 및 화학식 V의 화합물이다. 화학식 II의 화합물은 R1 및 R2 둘 다가 1 내지
