Patent ID: 8889835

Claim:
A method of preparing a modified dextran molecule comprising: (a) introducing carboxylic acid groups on a dextran molecule to make a carboxyl-modified dextran; (b) reacting multiple carboxylic acid groups of the carboxyl-modified dextran molecule with a carbodiimide and (i) an amine-containing acetylene molecule, or (ii) an amine-containing azide molecule to form an acetylene-derivatized or azide-derivatized dextran molecule; (c) reacting other carboxylic acid groups of the acetylene-derivatized or azide-derivatized dextran molecule with a carbodiimide and a maleimido amine to form a maleimide-appended, acetylene- or azide-derivatized, dextran molecule; (d) reacting (i) the maleimide-appended, acetylene-derivatized dextran molecule with an azide-derivatized drug moiety, or (ii) the maleimide-appended, azide-derivatized dextran molecule with an acetylene-derivatized drug moiety to form a maleimide-appended, drug modified dextran molecule; and (e) coupling the maleimide-appended, drug modified dextran molecule with a thiol-containing compound comprising a recognition moiety to form a recognition moiety-appended, drug-modified dextran molecule wherein click chemistry reaction between azide and acetylene is used only to attach drug moieties to the dextran and wherein the carboxyl-modified dextran molecule comprises between 44 and 100 carboxyl groups.