Polymeric alpha-hydroxy aldehyde and ketone reagents and conjugation method
Provided herein are polymeric α-hydroxy aldehyde or α-hydroxy ketone reagents which can be conjugated to amine-containing compounds to form stable conjugates in a single-step reaction. In selected embodiments, the polymeric reagent itself incorporates an internal proton-abstracting (basic) functional group, to promote more efficient reaction. The substituent is appropriately situated, via a linker if necessary, to position the group for proton abstraction, preferably providing a 4- or 5-bond spacing between the abstracting atom and the hydrogen atom on the α-carbon. Also provided are methods of using the reagents and stable, solubilized conjugates of the reagents with biologically active compounds. In preferred embodiments, the polymeric component of the reagent or conjugate is a polyethylene glycol.
1. A polymeric conjugate having the structure VI:
wherein:
(i) R 7 is —C(═O)—CHR 1 —NH-B, and R 8 is selected from —C(═O)OH, —CH 2 OH, —C(═O)N(R 1 ) 2 , —CH 2 N(R 1 ) 2 , —OH, and —N(R 1 ) 2 ; or
(ii) R 7 is —CHR 1 —C(═O)—CHR 1 —NH-B, and R 8 is —OH or —N(R 1 ) 2 ;
POLY is a water-soluble polymer;
—NH-B represents the residue of an amine-containing biologically active compound; and
each R 1 is independently selected from H, lower alkyl, and alkoxyalkyl.
2. The conjugate of claim 1 , wherein each R 1 is independently H or methyl.
3. The conjugate of claim 1 , wherein each R 1 is H.
4. The conjugate of claim 1 , wherein R 7 is —C(═O)—CHR 1 —NH—B, where R 1 is H or methyl, and R 8 is —C(═O)OH or —CH 2 NH 2 .
5. The conjugate of claim 1 , wherein R 7 is —CHR 1 —C(═O)—CHR 1 —NH—B, where each R 1 is independently H or methyl, and R 8 is —OH or —NH 2 .
6. The conjugate of claim 1 , wherein the amine-containing biologically active compound is a polypeptide or a protein.
7. The conjugate of claim 1 , wherein POLY is a poly(ethylene glycol).
8. The conjugate of claim 7 , wherein POLY is methoxy poly(ethylene glycol).
9. A pharmaceutical composition comprising the polymeric conjugate of claim 1 and a pharmaceutical excipient.
10. The pharmaceutical composition of claim 9 , wherein the composition is a solid.
11. The pharmaceutical composition of claim 9 , wherein the composition is a liquid.