To provide a technique for suppressing discoloration of an aqueous composition containing a halogenated isoquinoline derivative during preservation at high temperature.SOLUTION: A pharmaceutical preparation is obtained by storing an aqueous composition comprising a compound represented by general formula (1) in the figure, where X represents a halogen atom, or a salt thereof, or a solvate of them, in a container made of a polyolefin-based resin.SELECTED DRAWING: None【課題】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。【解決手段】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。【選択図】なし
