Patent No. 597960 Disclosed is biodegradable poly(ethylene glycol) based water-insoluble hydrogel comprising backbone moieties which are interconnected by hydrolytically degradable bonds, the backbone moieties are characterized by having a molecular weight in the range of from 1 kDa to 20 kDa and having the structure C*-(A-Hyp)x wherein C* is a branching core, A is a poly(ethylene glycol) based polymeric chain, Hyp is a hyperbranched dendritic moiety, x is an integer of from 3 to 16； and wherein the hyperbranched dendritic moiety further comprises reactive functional groups and interconnected functional groups. Also disclosed is a process for the preparation of a hydrogel comprising the step of reacting a backbone reagent having the formula I, wherein n is an integer from 3 to 100； with a crosslinker reagent of the following formula II, wherein q is an integer from 3 to 100； each m independently is an integer of from 2 to 4； in a ratio amine/active ester of 2: 1 to 1.05: 1, preferably resulting in a hydrogel loading of 0.02 to 2 mmol amine per g hydrogel； and wherein the reagents are dissolved in an aprotic solvent in the presence of a suitable base.
