Liposome composite body

1. A method for treating a tumor comprising:

administering to a subject in need thereof an effective amount of a liposome comprising an anti-cancer agent and a liposome membrane-constituting substance, wherein the liposome membrane-constituting substance is (a) anchored in the hydrophobic membrane region of a liposome and (b) covalently bonded to a light-absorbing compound having an absorption wavelength in the near-infrared region, the light-absorbing compound comprising an indocyanine green dye, the anti-cancer agent being contained in the liposome; and

irradiating an affected area of the subject with light;

wherein the liposome membrane-constituting substance covalently bonded to the light-absorbing compound is represented by formula (I) below:

A-(CH 2 ) a -B 1 -(CH 2 ) b -B 2 -D-E 1   (I)

wherein A represents the light-absorbing compound;

B 1 and B 2 each independently represent —CH 2 —, —CH═CH—, —O—, —S—, —NH—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —PO 4 H—, or —PO 4 M- (where M represents an alkali metal ion);

D represents —CHE 2 -, —CH 2 CH(OCOE 2 )-CH 2 OCO—, or —CHE 2 -CH 2 OCO—;

E 1 represents a substituted or unsubstituted hydrocarbon group having 8 to 18 carbon atoms;

E 2 represents hydrogen or a substituted or unsubstituted hydrocarbon group having 8 to 18 carbon atoms; and

a represents an integer of 0 to 4 and b represents an integer of 0 to 6.

2. The method according to claim 1 , comprising irradiating the affected area with light to generate singlet oxygen.

3. The method according to claim 1 , wherein the liposome membrane-constituting substance comprises a lipid.

4. The method according to claim 1 , wherein B 1 and B 2 each independently represent —CH 2 —, —CH═CH—, —O—, or —S—; and D represents —CHE 2 - (where E 2 is as described in claim 1 ).

5. The method according to claim 1 , wherein B 1 and B 2 each represent —CH 2 —.

6. The method according to claim 1 , wherein the liposome membrane-constituting substance comprises at least one selected from the group consisting of lipids, membrane stabilizers, antioxidants, and membrane proteins.

7. The method according to claim 1 , wherein the liposome membrane-constituting substance covalently bonded to the light-absorbing compound is represented by formula (II-1) below:

wherein X 1 and X 2 each represent —C(CH 3 ) 2 —, O, or S; Y 1 and Y 3 each represent hydrogen or OCH 3 and Y 2 and Y 4 each represent hydrogen, or Y 1 and Y 2 , and Y 3 and Y 4 each optionally together form a benzene ring fused with a ring to which they are bound; Q 1 and Q 2 each represent hydrogen or are optionally bonded to form a 6-membered ring; any one of R 1 to R 3 represents —(CH 2 ) a -B 1 -(CH 2 ) b -B 2 -D-E 1 where the symbols have the same meaning as those in the formula (I) in claim 1 ; P 1 represents chloride ion, bromide ion, or iodide ion as a monovalent anion; and R 1 to R 3 each represent a group selected from the group consisting of the following groups:

where Z 1 or Z 2 represents —O—, —NH—, —S—, —SO 2 —, —CH═CH—, —SO 2 NH—, —NHSO 2 —, —CONH—, —NHCO—, —CO—, —COO—, —OCO—, or —C 6 H 4 —; P 2 represents hydrogen ion, lithium ion, sodium ion, or potassium ion as a monovalent cation; M represents hydrogen ion, lithium ion, sodium ion, or potassium ion as a monovalent cation; R 4 represents an alkane, an alkene, or an alkyne having 1 to 18 carbon atoms; n or m represents an integer of 0 to 22; 1 represents an integer of 1 to 22; p represents an integer of 0 to 17; and x represents an integer of 2 to 2,000.

8. The method according to claim 1 , wherein the liposome membrane-constituting substance covalently bonded to the light-absorbing compound is represented by formula (5) below:

9. The method according to claim 1 , wherein the liposome membrane-constituting substance covalently bonded to the light-absorbing compound is represented by the formula below: