PROBLEM TO BE SOLVED: To provide a method of producing an aqueous pharmaceutical composition containing oxaliplatin that is stable over time and a method of stabilizing the aqueous pharmaceutical composition containing oxaliplatin, which are based on inhibiting decomposition of oxaliplatin dissolved in water.SOLUTION: An aqueous pharmaceutical composition contains oxaliplatin and water. To the water or the aqueous pharmaceutical composition, lactose or a hydrate thereof is added that satisfies one or both of (1) a cumulative diameter D10 being 10 μm or more and a D50 being 100 μm or less as obtained by a laser diffraction/scattering particle size distribution measurement method, and (2) the specific absorbance of the aqueous solution in wavelength of 270-300 nm being 0.015 or less.SELECTED DRAWING: NoneCOPYRIGHT: (C)2017,JPO&INPIT【課題】水に溶解されたオキサリプラチンの分解抑制に基づく、経時的に安定なオキサリプラチンを含む水性医薬組成物の製造方法、並びに、オキサリプラチンを含む水性医薬組成物の安定化方法を提供すること。【解決手段】オキサリプラチン及び水を含む水性医薬組成物の当該水又は当該水性医薬組成物に(1)レーザー回折散乱式粒度分布測定法による体積累積径D10が10μm以上であり、D50が100μm以下、(2)波長270~300nmにおける水溶液の比吸光度が0.015以下である、のいずれか又は両方を満たす乳糖又はその水和物を添加する。【選択図】なし
