The present invention provides a solubility enhancement preparation of hardly soluble drug by oral absorption, which is characterized by comprising:(A) a granulated substance comprising 1) hardly soluble drug that has acidic group in the molecule, 2) alkali agent, and 3) surfactant, and substantially without disintegrator； and(B) a disintegrator that only exists outside the granulated substance.本發明提供一種用以提高難溶性藥物的經口吸收性之溶解性改善製劑，其特徵為包含：(A)1)含有分子內具有酸性基之難溶性藥物、2)鹼劑及3)界面活性劑，且實質上不含崩散劑(disintegrator)之造粒物；以及(B)僅存在於該造粒物外部之崩散劑。
