[Problem] There has been a requirement for a process forproducing a pharmaceutical preparation that is obtained byencapsulating a uniform poorly water-soluble drug in a blockcopolymer, 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-blockcopolymer composite, the method comprising: mixing a poorlywater-soluble drug and a block copolymer including ahydrophilic segment and a hydrophobic segment bonded together,in one or more non-aqueous solvents； optionally heating themixture as necessary； and spray-drying the resulting mixtureliquid.
