Patent ID: 7897176

Claim:
A composition comprising organic-inorganic hybrid particles having a biologically active substance carried thereon, wherein the particles are formed from a block copolymer having a structure represented by any one of the following Formulas (II-a), (II-b), (III-a) and (III-b): where in the respective formulas, A, L, T, m, x, y and z each have the following independent meanings; A represents a hydrogen atom or a substituted or unsubstituted alkyl group having up to 12 carbon atoms; L represents a single bond, NH, CO or X(CH 2 ) p Y, in which X represents OCO, OCONH, NHCO, NHCOO, NHCONH, CONH or COO; Y represents NH or CO; and p represents an integer of 1 to 6; T represents a hydrogen atom, a hydroxyl group or —ZR, in which Z represents a single bond, CO, O or NH, and R represents a substituted or unsubstituted hydrocarbon group having up to 12 carbon atoms; m represents an integer of 4 to 2500; and x+y or z represents an integer of 5 to 300, a calcium ion (Ca +2 ), a phosphoric acid ion (PO 4 3− ) and the biologically active substance, and the particles have an average particle diameter of 50 to 600 nm in an aqueous dispersion, and are substantially spherical, wherein the calcium ion is present in the hybrid particles in an amount which is excessive to the phosphoric acid ion as compared with an equivalent required for forming hydroxyapatite, and wherein the organic-inorganic hybrid particles comprise 30 to 70% by weight of the block copolymer, 25 to 65% by weight of hydroxyapatite and 0.1 to 15% by weight of the biologically active substance each based on the whole weight of the particles.