Amphiphilic compound, and medical resin composition and pharmaceutical additive using the same

An amphiphilic compound comprising:

• a moiety (I) including a constitutional unit (A);
• and
• a hydrocarbon group having 8 or more carbon atoms,
• wherein the constitutional unit (A) includes a constitutional unit represented by chemical formula (1):
• wherein R1 represents a hydrogen atom or a methyl group, and X represents —C(═O)—O—, —C(═O)—NH—, —O—, —CH2O—, or —CH2CH2O—,
• the hydrocarbon group having 8 or more carbon atoms is bonded to the moiety (I) via a divalent bonding group containing a group selected from the group consisting of —S—, —S—C(═S)—, —S—C(═S)—S—, —S—C(═S)—N(—Ra)—, —S—C(═S)—O—, —S—Rb—C(═O)—O—, —S—Rb—C(═O)—N(—Ra)—, —S—Rb—O—, —S—Rb—O—C(═O)—, and —N(—Ra)—C(═O)—, wherein Ra is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and Rb is a hydrocarbon group having 1 to 30 carbon atoms.