A prodrug or a pharmaceutically acceptable salt thereof comprising an insulin linker conjugate D-L, wherein D represents the insulin moiety; and -L is a non-biologically active linker moiety -L 1 represented by formula, wherein the dashed line indicates the attachment to one of the amino groups of the insulin by forming an amide bond; X is C(R 3 R 3a); or N(R 3); R 1a, R 3a are independently selected from the group consisting H, NH(R 2b), N(R 2b)C R 4 and C 1-4 alkyl; R 1, R 2 R 2a, R 2b, R 3, R 4 are independently selected from the group consisting of H and C 1-4 alkyl, wherein L 1 is substituted with one L 2 -Z, provided that the hydrogen marked with the asterisk in formula is not replaced by a substituent and wherein L 2 is a single chemical bond or L 2 is a C 1-20 alkyl chain, which is optionally interrupted by one or more groups independently selected from -O-; and C N(R 3aa); optionally substituted with one or more groups independently selected from OH; and C N(R 3aa R 3aaa); and wherein R 3aa, R 3aaa are independently selected from the group consisting of H; and C 1-4 alkyl; and wherein L 2 is attached to Z via a terminal group selected from and Z is a hydrogel; wherein the hydrogel Z is a biodegradable poly(ethylene glycol) based water-insoluble hydrogel; wherein the hydrogel is composed of backbone moieties interconnected by hydrolytically degradable bonds; wherein the backbone moiety has a quarternary carbon of formula C(A-Hyp) 4, wherein each A is independently selected from the formula -(CH 2) n1 (OCH 2 CH 2) n X'-, wherein n1 is 1 or 2; n is an integer in the range of from 5 to 50; and X' is an amide linkage covalently linking A and Hyp, wherein each Hyp is a hyperbranched polypeptide comprised of between 5 and 32 lysines in bound form and wherein Hyp is selected of the same or different dendritic moieties Hyp; wherein backbone moieties are linked together through crosslinker moieties, each crosslinker moiety being terminated by at least two of the hydrolytically degradable bonds; wherein the crosslinker is a one PEG based molecular chain, comprising at least each m ethylene glycol units, wherein m is an integer in the range of from 3 to 100. D represents the insulin moiety; and -L is a non-biologically active linker moiety -L 1 represented by formula, wherein the dashed line indicates the attachment to one of the amino groups of the insulin by forming an amide bond; X is C(R 3 R 3a); or N(R 3); R 1a, R 3a are independently selected from the group consisting H, NH(R 2b), N(R 2b)C R 4 and C 1-4 alkyl; R 1, R 2 R 2a, R 2b, R 3, R 4 are independently selected from the group consisting of H and C 1-4 alkyl, wherein L 1 is substituted with one L 2 -Z, provided that the hydrogen marked with the asterisk in formula is not replaced by a substituent and wherein L 2 is a single chemical bond or L 2 is a C 1-20 alkyl chain, which is optionally interrupted by one or more groups independently selected from -O-; and C N(R 3aa); optionally substituted with one or more groups independently selected from OH; and C N(R 3aa R 3aaa); and wherein R 3aa, R 3aaa are independently selected from the group consisting of H; and C 1-4 alkyl; and wherein L 2 is attached to Z via a terminal group selected from Z is a hydrogel; wherein the hydrogel Z is a biodegradable poly(ethylene glycol) based water-insoluble hydrogel; wherein the hydrogel is composed of backbone moieties interconnected by hydrolytically degradable bonds; wherein the backbone moiety has a quarternary carbon of formula C(A-Hyp) 4, wherein each A is independently selected from the formula -(CH 2) n1 (OCH 2 CH 2) n X'-, wherein n1 is 1 or 2; n is an integer in the range of from 5 to 50; and X' is an amide linkage covalently linking A and Hyp, wherein each Hyp is a hyperbranched polypeptide comprised of between 5 and 32 lysines in bound form and wherein Hyp is selected of the same or different dendritic moieties Hyp; wherein backbone moieties are linked together through crosslinker moieties, each crosslinker moiety being terminated by at least two of the hydrolytically degradable bonds; wherein the crosslinker is a one PEG based molecular chain, comprising at least each m ethylene glycol units, wherein m is an integer in the range of from 3 to 100.