Disclosed is a particulate medicinal composition, which is suitable for a drug delivery system, having an improved drug-encapsulation stability. Specifically disclosed is a particulate medicinal composition (1) comprising block copolymer units (2), the block copolymer units being radially arranged with hydrophobic polymer chain segments (2b) facing inward and hydrophilic polymer chain segments (2a) facing outward, a drug (4) comprising a biopolymer, and a charged lipid (3) which is charged oppositely to the charge of the drug (4), wherein said charged lipid (3) is arranged in a state of being attracted toward the hydrophobic polymer chain segment (2b) side and the drug (3) is positioned inside of the hydrophobic polymer chain segments (2b). In this medicinal composition (1), drop off of the drug (4) outside particles can be remarkably prevented.
