Patent ID: 7829074

Claim:
A method for preparing a bioactive agent hydroxyapatite-targeting polymer conjugate, said method comprising the steps of: a. providing an isolated water-soluble polymer comprising, at a first terminus, a hydroxyapatite-targeting moiety, and at a second terminus, a reactive group suitable for reacting with a functional group of a biologically active agent, and b. reacting said isolated water-soluble polymer from step (a) with a biologically active agent comprising said functional group under conditions effective to form a covalently bonded biologically active agent-water-soluble polymer-hydroxyapatite targeting conjugate, wherein said biologically active agent comprises multiple functional groups suitable for reacting with said reactive group, and said reacting step is carried out under conditions effective to form a mixture of biologically active agent-water-soluble polymer-hydroxyapatite targeting conjugates, wherein said mixture comprises different conjugate multimer species each having a different number of hydroxyapatite-targeting-water-soluble polymers covalently attached to said biologically active agent, wherein said mixture is purified to separate each of the conjugate multimer species.