Abstract: Provided is a compound (Z) represented by the formula (1) or (2) below. In the formulas (1) and (2), Xs in each of the formulas (1) and (2) are each independently a carboxy group, a carboxylate group, or a monovalent group represented by the formula (3); at least one of Xs in each of the formulas (1) and (2) is a carboxy group or a carboxylate group; and at least one of Xs in each of the formulas (1) and (2) is a monovalent group represented by the formula (3) —C(O)—Y-(AO)n—R (3). In the formula (3), —Y— is —O—, —NH—, or —S—; A is a C2-C4 alkylene group; R is a hydrogen atom or a C1-C15 monovalent hydrocarbon group in which a hydrogen atom is optionally substituted with a C1-C10 alkoxy group; n is an integer of 4 to 1000; at least one of n As is an ethylene group; and when the formulas (1) and (2) each have multiple monovalent groups represented by the formula (3), each of —Y—, A, R, and n is the same or different among the monovalent groups.

Abstract: The present invention provides a raw material for bulk drugs and a pharmaceutical additive which provide excellent formulation stability and excellent over-time stability of drug efficacy when used to modify a bulk drug, a polypeptide, a bioactive protein, an enzyme, and the like. The present invention relates to a raw material for bulk drugs or a pharmaceutical additive, containing: a polyether composition (A) represented by formula (1), wherein the polyether composition (A) has a unimodal molecular weight distribution, the polyether composition (A) has a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 1.

Abstract: The present invention provides a raw material for bulk drugs and a pharmaceutical additive which provide excellent formulation stability and excellent over-time stability of drug efficacy when used to modify a bulk drug, a polypeptide, a bioactive protein, an enzyme, and the like. The present invention relates to a raw material for bulk drugs or a pharmaceutical additive, containing: a polyether composition (A) represented by formula (1), wherein the polyether composition (A) has a unimodal molecular weight distribution, the polyether composition (A) has a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 1.