Composition having a conjugate of a dye and polyethylene glycol and an additive, and a contrast agent for photoacoustic imaging having the composition

摘要

PROBLEM TO BE SOLVED: To provide a photoacoustic-imaging contrast agent which has high clustering properties to a tumor, leaves little residue in blood, and is capable of administration into blood.SOLUTION: The invention provides a photoacoustic-imaging contrast agent consisting of a conjugate (A) of a pigment and a polyethylene glycol, the pigment having, as a basic skeleton, a bisindole structure constructed by binding a methine chain to a five-membered ring comprising N at both ends of the methine chain; and additives (B), such as cyclodextrin, which interact with the conjugate. After the administration into blood, the aggregate of (A) and (B) is transferred from blood to a tumor, while the aggregate remaining in blood is dissolved and discharged from the body.SELECTED DRAWING: Figure 1