PROBLEM TO BE SOLVED: To provide a liposomal preparation capable of delivering a multivalent ionic drug with good targeting ability and releasing the drug in the targeted tissues effectively.SOLUTION: A liposomal pharmaceutical preparation comprises a multivalent ionic drug, such as mitoxantrone, vincristine, vinorelbine and vinblastine, as an active ingredient, which has two or more dissociable groups with a dissociation constant of 4.5-9.5. The liposome has a size of 30-80 nm. The bilayer of the liposome comprises a phospholipid with a phase transition temperature higher than the body temperature, cholesterol, and a hydrophilic polymer-modified lipid. The intraliposomal phase of the liposome comprises a multivalent counter ion. The phospholipid with a phase transition temperature (Tm) higher than the body temperature is 50-100 mol/mol% relative to the total content of the phospholipids in the bilayer.【課題】多価イオン性薬物を良好な標的化能で送達し、且つ標的組織で効果的に薬物を放出することが可能なリポソーム製剤の提供。【解決手段】有効成分として解離定数が4.5~9.5の2つ以上の解離基を有するミトキサントロン、ビンクリスチン、ビノレルビン、ビンブラスチン等の多価イオン性薬物を含み、リポソームの大きさが30~80nmであり、該リポソームの二重層が、相転移温度が体温よりも高いリン脂質、コレステロール及び親水性ポリマー修飾脂質を含み、該リポソームのリポソーム内相が多価対イオンを含み、且つ相転移温度(Tm)が体温よりも高いリン脂質が、前記二重層中のリン脂質の合計含量に対して、50~100mol/mol%であるリポソーム医薬製剤。【選択図】なし