Tethering drug substances to it gel network is all effective way of controlling the release kinetics of hydrogel-based drug delivery systems Here, we report oil in situ forming, biodegradable hydrogels that allow for the covalent attachment of peptides or proteins. Hydrogels were prepared by step-growth polymerization of branched poly(ethylene glycol). The gel strength ranged from 1075 to 2435 Pit: the degradation time varied between 24 and 120 h. Fluorescence recovery after photobleaching showed that fluorescently labeled bovine serum albumin (FITC-BSA) was Successfully bound to the gel network during gel formation Within 168 h, the mobility of the tethered molecules gradually increased due to polymer degradation Using FITC-BSA and lysozyme as model proteins, we showed the potential of the developed hydrogels for time-controlled release. The obtained release profiles had a sigmoidal shape and matched the degradation profile very well. protein release wits complete after 96 h