Patent ID: 7365127

Claim:
A process for preparing an activated polymer having a multifunctional linking moiety thereon, comprising: a) reacting an activatable polymer residue with an activating agent capable of providing a leaving group thereon to provide a first reaction mixture containing an activated polymer residue and said activatable polymer residue; b) reacting said first reaction mixture with a multi-functional linking moiety having a protecting group thereon which is unreactive with said activated polymer residue under conditions wherein said activated polymer residue of the first reaction mixture is present in excess with respect to said multi-functional linking moiety to form a second reaction mixture containing said first reaction mixture and an intermediate polymer containing the protecting group resulting from said reacting of said activated polymer residue with said multi-functional linking moiety; c) quenching said second reaction mixture with a sufficient amount of a first quenching agent to inactivate the activated polymer residue therein forming a third reaction mixture containing said intermediate polymer; d) adding a sufficient amount of a second quenching agent to said third reaction mixture to inactivate the activatable polymer residue therein and form a fourth reaction mixture containing said intermediate polymer; e) removing the protecting group from the intermediate polymer and neutralizing said fourth reaction mixture to form a fifth reaction mixture containing a deprotected intermediate polymer; and f) reacting said fifth reaction mixture with a compound capable of activating the deprotected intermediate polymer therein for linking to a biologically active moiety and form a sixth reaction mixture containing an activated polymer having a multifunctional linking moiety thereon.