Provided is a technology of inhibiting a change in color of a halogenated isoquinoline derivative-containing aqueous composition during storage at high temperature. This pharmaceutical preparation comprises an aqueous composition which contains a compound represented by general formula (1) [where, X represents a halogen atom] or a salt thereof, or a solvate thereof, and which is contained in a polyolefin resin container.本發明係提供抑制含有鹵化異喹啉衍生物之水性組成物，在高溫保存時發生變色的技術。本發明的醫藥製劑，係將含有下述一般式(1)：[式中、X係表示鹵原子。]所示化合物或其鹽或該等的溶劑合物之水性組成物，收容於聚烯烴系樹脂製容器中。
