To provide a technique for improving the stability of a halogenated isoquinoline derivative with respect to light in an aqueous composition.SOLUTION: In a pharmaceutical preparation, 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 is received in a package that blocks a ray with a wavelength of 300 to 335 nm.SELECTED DRAWING: None【課題】ハロゲン化イソキノリン誘導体の、水性組成物中での光に対する安定性を改善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、波長３００～３３５ｎｍの光線を遮断する包装体に収容されてなる、医薬製剤。【選択図】なし
