Tertiary amine compound or imine compound-polymer conjugate and production method therefor

A compound represented by Formula (I) or a pharmaceutically acceptable salt thereof;

• in Formula (I), D+ is a structure forming a quaternary ammonium salt or an iminium salt from D, a tertiary amine compound or an imine compound;
• a nitrogen atom forming the quaternary ammonium salt or the iminium salt and a carbon atom to which R1 and R2 bond are bonded to each other, R1 and R2 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aromatic group, or a substituted or unsubstituted heterocyclic group;
• A is a bivalent hydrocarbon group in which a carbon other than carbons at both ends may be substituted with a hetero atom selected from the group consisting of an oxygen atom, a nitrogen atom and a sulfur atom;
• any two or three groups of R1, R2, and A may combine together to form a ring;
• and Poly is a polymer residue having a carboxy group.