Degradable cationic lipid containing a disulfide bond and applications thereof

A cationic lipid containing a disulfide bond, the structure of which is represented by general formula (1):

• or salt, tautomer, stereoisomer, isotopically substituted derivative, or solvate thereof,
• wherein, —S—S— is a disulfide bond;
• L1 and L2 are each independently —(CH2)t-Ld-(CH2)t— or —(CH2)t-Ld-(CH2)t-Ld-(CH2)t—, wherein each t is independently an integer from 1 to 4;
• each Ld is independently —NHC(═Y1)Y2— or —Y2C(═Y1)NH—, wherein Y1 and Y2 are each independently O, S, or NH;
• X1 and X2 are each independently an acyclic divalent linking group containing a tertiary amine group;
• G1 and G2 are each independently a linking bond or a trivalent branching group;
• when G1 is a linking bond, k1 is 1;
• when G1 is a trivalent branching group, k1 is 2;
• when G2 is a linking bond, k2 is 1;
• when G2 is a trivalent branching group, k2 is 2;
• L3 and L4 are, at each occurrence, each independently selected from the group consisting of a linking bond, —(CH2)q—, Z, P0,
• and combinations thereof, wherein, q is an integer from 1 to 10, Z is selected from the group consisting of —O—, —S—, —OC(═O)—, —C(═O)O—, —OC(═O)O—, —C(═O)—, —C(═O)S—, —SC(═O)—, —NRc—, —NRcC(═O)—, —C(═O)NRc—, —NRcC(═O)NRc—, —OC(═O)NRc—, —NRcC(═O)O—, —SC(═O)NRc—, —NRcC(═O)S—, —C(Rc)═N—NRc—, —NRc—N═C(Rc)—, and —CH(OH)—, Rc is, at each occurrence, independently H or a methyl group;
• P0 is
• and p is, at each occurrence, independently 0 or 1;
• R1 and R2 are each independently a substituted or unsubstituted C5-30 hydrocarbon group or C5-30 hydrocarbon derivative residue.