The present invention relates to a polymeric prodrug comprising a hydrogel having cross-linkers and a non-biodegradable backbone, a biologically active moiety to be released as drug and a reversible prodrug linker, wherein the prodrug linker covalently links the hydrogel and the biologically active moiety at a position and wherein the prodrug linker is attached to the non-biodegradable backbone of the hydrogel and the hydrogel has a plurality of pores with openings on the surface of the hydrogel, wherein the diameter of the pores is larger than the biologically active moiety at least at all points of the pore between at least one of the openings and the position of the biologically active moiety and wherein the cross-linkers of the hydrogel further comprise bio-degradable bonds selected from the group of chemically cleavable bonds consisting of phosphate, phosphonate, carbonate, carbamate, disulfide and ester bonds, wherein the number of crosslinks and the halflife of the bio-degradable bonds are adjusted in that almost all drug can be released before a significant amount of release of backbone can take place.The present invention also relates to respective hydrogels and methods for the manufacture of a mesoporous hydrogel-biologically active moiety conjugate.
