To provide a technique for suppressing discoloration of a halogenated isoquinoline derivative-containing aqueous composition during high-temperature storage. The following general formula (1) [wherein X represents a halogen atom. ] The pharmaceutical formulation in which the aqueous composition containing the compound or its salt represented by these, or those solvates is accommodated in the container made from polyolefin resin.ハロゲン化イソキノリン誘導体含有水性組成物の、高温保存時の変色を抑制する技術を提供すること。 次の一般式（１）［式中、Ｘはハロゲン原子を示す。］で表される化合物若しくはその塩又はそれらの溶媒和物を含有する水性組成物が、ポリオレフィン系樹脂製容器に収容されてなる、医薬製剤。
