[Problem] There has been a requirement for a process for producing a pharmaceutical preparation that is obtained by encapsulating a uniform poorly water-soluble drug in a block copolymer, and dissolves immediately with an addition of water, and does not contain residues of organic solvents. [Solution] Provided is a method for producing a drug-block copolymer composite, the method comprising: mixing a poorly water-soluble drug and a block copolymer including a hydrophilic segment and a hydrophobic segment bonded together, in one or more non-aqueous solvents； optionally heating the mixture as necessary； and spray-drying the resulting mixture liquid.本發明之課題在於謀求一種不殘留有機溶劑，藉由添加水而迅速溶解，均勻地使水難溶性藥物內包於嵌段共聚物中所獲得之醫藥製劑之製造方法。本發明提供一種藥物-嵌段共聚物複合體之製造方法，其特徵在於：將水難溶性藥物、及使親水性鏈段與疏水性鏈段鍵結而成之嵌段共聚物混合於1種或2種以上之非水性溶劑中，視需要進行加熱並對所得之混合液進行噴霧乾燥。
