A compound of formula (XII): or a pharmaceutically acceptable salt or solvate thereof, wherein: n is an integer from 10 to 500; m is an integer from 1 to 5; w is an integer from 1 to 5; GC is a moiety of a glucocorticoid drug molecule; A is absent, C 1 -C 6 alkylene, or C 6 -C 10 arylene; B is absent, NR 4 , O, or C(O); D is absent, NR 4 , O, C(O), or CR 5 R 5 ; E is absent, C 1 -C 6 alkylene, or a linker comprising a branched structure capable of connecting to two or more R 2 groups, said linker optionally comprising one, two, or more heteroatoms independently selected from the group consisting of O, S, and N; G is absent, NR 4 , or O; P is absent or C(O); Q is absent, C 6 -C 10 arylene, or C 1 -C 6 alkylene; T is absent, C 1 -C 6 alkylene, C 6 -C 10 arylene, or C(O); X is absent, O, S, or NR 4 ; Y is absent, C(O), C 6 -C 10 arylene, or C 1 -C 6 alkylene; Z is absent, NR 4 , O, C 1 -C 6 alkylene, or a linker comprising a branched structure capable of connecting to one or more dexamethasone moieties, said linker optionally comprising one or more heteroatoms independently selected from the group consisting of O, S, and N; R 1 is H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 6 -C 10 aryl, 5-10 membered heteroaryl, or 5-10 membered heterocyclyl, each group except H optionally substituted by one to five substituents independently selected from the group consisting of C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, halogen, oxo (=O), -NR a R b , -NO 2 , -CN, -OR 3 , and -SR 3 ; or alternatively, R 1 is -CH 2 -A-B-D-E-(R 2 ) m ; R 3 at each occurrence is independently H, C 1 -C 4 alkyl, or C 1 -C 4 haloalkyl; R 4 at each occurrence is independently H or C 1 -C 4 alkyl; R 5 at each occurrence is independently H, C 1 -C 4 alkyl, or C 1 -C 4 haloalkyl; R a and R b are each independently H or C 1 -C 4 alkyl; and wherein when any of groups A, B, D, E, G, P, Q, T, X, Y, and Z is absent, its two available adjacent groups are single-bonded to each other directly. n is an integer from 10 to 500; m is an integer from 1 to 5; w is an integer from 1 to 5; GC is a moiety of a glucocorticoid drug molecule; A is absent, C 1 -C 6 alkylene, or C 6 -C 10 arylene; B is absent, NR 4 , O, or C(O); D is absent, NR 4 , O, C(O), or CR 5 R 5 ; E is absent, C 1 -C 6 alkylene, or a linker comprising a branched structure capable of connecting to two or more R 2 groups, said linker optionally comprising one, two, or more heteroatoms independently selected from the group consisting of O, S, and N; G is absent, NR 4 , or O; P is absent or C(O); Q is absent, C 6 -C 10 arylene, or C 1 -C 6 alkylene; T is absent, C 1 -C 6 alkylene, C 6 -C 10 arylene, or C(O); X is absent, O, S, or NR 4 ; Y is absent, C(O), C 6 -C 10 arylene, or C 1 -C 6 alkylene; Z is absent, NR 4 , O, C 1 -C 6 alkylene, or a linker comprising a branched structure capable of connecting to one or more dexamethasone moieties, said linker optionally comprising one or more heteroatoms independently selected from the group consisting of O, S, and N; R 1 is H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 6 -C 10 aryl, 5-10 membered heteroaryl, or 5-10 membered heterocyclyl, each group except H optionally substituted by one to five substituents independently selected from the group consisting of C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, halogen, oxo (=O), -NR a R b , -NO 2 , -CN, -OR 3 , and -SR 3 ; or alternatively, R 1 is -CH 2 -A-B-D-E-(R 2 ) m ; R 3 at each occurrence is independently H, C 1 -C 4 alkyl, or C 1 -C 4 haloalkyl; R 4 at each occurrence is independently H or C 1 -C 4 alkyl; R 5 at each occurrence is independently H, C 1 -C 4 alkyl, or C 1 -C 4 haloalkyl; R a and R b are each independently H or C 1 -C 4 alkyl; and wherein when any of groups A, B, D, E, G, P, Q, T, X, Y, and Z is absent, its two available adjacent groups are single-bonded to each other directly. <EOS>