Stabilized polymeric thiol reagents
View Patent ↗Disclosed are water soluble polymeric reagents comprising the structure POLY-[Y—S—W] x , where POLY is a water soluble polymer; Y is a hydrocarbon-based spacer group, x is 1 to 25, and S—W is a thiol, protected thiol, or thiol-reactive derivative. Preferably, the water soluble polymer is a PEG polymer. Also disclosed are conjugates of such polymeric reagents with pharmaceutically relevant molecules, and methods of their formation and use.
1. A water-soluble polymeric reagent of the structure:
POLY-[Y—S—W] x
wherein:
POLY is a water soluble polymer;
Y has the formula —(CR 1 R 2 )n-, where n is 3 to 8, and each of R 1 and R 2 is independently selected from hydrogen, lower alkyl, lower alkenyl, and a non-interfering substituent, where two groups R 1 and R 2 on different carbon atoms may be linked to form a cycloalkyl or aryl group;
S is a sulfur atom attached to an sp 3 hybridized carbon of Y;
S—W is a thiol, protected thiol, or thiol-reactive thiol derivative;
x=1-25; and
if POLY is a linear polyethylene glycol, x=1, and Y is a linear alkyl chain then POLY has a molecular weight of at least 500,
wherein when S—W is the disulfide linkage ortho-pyridyl disulfide and POLY is a linear polyethylene glycol, at least one R 1 on a carbon adjacent to said disulfide linkage is lower alkyl.
2. The reagent of claim 1 , wherein x is 1 or 2.
3. The reagent of claim 1 , wherein POLY is a polyethylene glycol.
4. The reagent of claim 1 , wherein S—W is a thiol-reactive thiol derivative.
5. The reagent of claim 4 , wherein S—W is ortho-pyridyl disulfide (OPSS).
6. The reagent of claim 4 , wherein said polyethylene glycol has a molecular weight of 1000 to about 100,000 Daltons and a morphology selected from linear, branched, forked, and multiarmed.
7. The reagent of claim 1 , wherein Y is selected from the group consisting of C 4 -C 8 alkylene, C 5 -C 8 cycloalkylene, and combinations thereof.
8. The reagent of claim 1 , wherein n is 3 to 6, and each of R 1 and R 2 is independently selected from hydrogen and methyl.
9. The reagent of claim 1 , wherein each of R 1 and R 2 is hydrogen with the exception of R 1 on a carbon adjacent said sulfur atom, said R 1 being lower alkyl.
10. The reagent of claim 9 , wherein said lower alkyl is methyl or ethyl.
11. The reagent of claim 10 , wherein said lower alkyl is methyl.
12. The reagent of claim 1 , wherein two groups R 1 and R 2 on different carbon atoms are linked to form a cycloalkyl or aryl group.
13. The reagent of claim 12 , wherein Y comprises a cyclopentyl or cyclohexyl group.
14. The reagent of claim 1 , wherein said non-interfering substituents are selected from the group consisting of C 3 -C 6 cycloalkyl, halo, cyano, lower alkoxy, and phenyl.
15. A water-soluble polymeric reagent of the structure:
POLY-[Y—S—W] x
wherein:
POLY is a water soluble polymer;
Y has the formula —(CR 1 R 2 )n-, where n is 3 to 8, and each of R 1 and R 2 is independently selected from hydrogen, lower alkyl, lower alkenyl, and a non-interfering substituent, where two groups R 1 and R 2 on different carbon atoms may be linked to form a cycloalkyl or aryl group;
S is a sulfur atom attached to an sp 3 hybridized carbon of Y;
x is 2-25; and
S—W is a thiol, protected thiol, or thiol-reactive thiol derivative,
wherein when S—W is the disulfide linkage ortho-pyridyl disulfide and POLY is a linear polyethylene glycol, at least one R 1 on a carbon adjacent to said disulfide linkage is lower alkyl.
16. The reagent of claim 15 , where n is 3 to 6.
17. The reagent of claim 15 , wherein each of R 1 and R 2 is hydrogen.
18. The reagent of claim 15 , wherein for at least one Y, each of R 1 and R 2 is hydrogen with the exception of R 1 on a carbon adjacent said sulfur atom, said R 1 being lower alkyl.
19. The reagent of claim 18 , wherein x is 2.