Methods for forming polymer-drug conjugates

1. A method of preparing a conjugate comprising the step of contacting a polymeric reagent with an active agent under suitable conjugation conditions to thereby provide the conjugate, wherein the polymeric reagent has the following structure

wherein:

POLY 1 is a water-soluble polymer selected from the group consisting of poly(alkylene oxide), poly(vinyl pyrrolidone), poly(vinyl alcohol), polyoxazoline and poly(N-acryloylmorpholine);

POLY 2 is a water-soluble polymer selected from the group consisting of poly(alkylene oxide), poly(vinyl pyrrolidone), poly(vinyl alcohol), polyoxazoline and poly(N-acryloylmorpholine);

(a) is 0, 1, 2 or 3;

(b) is 0, 1, 2 or 3;

(e) is 0, 1, 2 or 3;

(f′) is 0, 1, 2 or 3;

(g′) is 0, 1, 2 or 3;

(h) is 0, 1, 2 or 3;

(j) is 0 to 20;

each R 1 is independently H or an organic radical selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl and substituted aryl;

X 1 , when present, is a first spacer moiety;

X 2 , when present, is a second spacer moiety;

X 5 , when present, is a fifth spacer moiety;

X 6 , when present, is a sixth spacer moiety;

X 7 , when present, is a seventh spacer moiety;

X 8 , when present, is an eighth spacer moiety;

R 5 is a branching moiety selected from the group consisting of

 wherein (p) is 1-10 and (q) is 1-10; and

Z is a reactive group suitable for reaction with an electrophile or nucleophile of the active agent.

2. The method of claim 1 , wherein each R 1 is H.

3. The method of claim 1 , wherein each R 1 is an organic radical and is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl and substituted aryl.

4. The method of claim 1 , wherein each water-soluble polymer is a poly(alkylene oxide).

5. The method of claim 4 , wherein each poly(alkylene oxide) is a poly(ethylene glycol).

6. The method of claim 5 , wherein each poly(ethylene glycol) is terminally capped with methoxy.

7. The method of claim 5 , wherein each poly(ethylene glycol) has a molecular weight of from about 100 Daltons to about 100,000 Daltons.

8. The method of claim 7 , wherein each poly(ethylene glycol) has a molecular weight of from about 1,000 Daltons to about 60,000 Daltons.

9. The method of claim 8 , wherein each poly(ethylene glycol) has a molecular weight of from about 2,000 Daltons to about 50,000 Daltons.

10. The method of claim 1 , wherein the reactive group reactive group is selected from the group consisting of hydroxyl, ester, ester, orthoester, carbonate, carbonate, acetal, aldehyde, aldehyde hydrate, ketone, vinyl ketone, ketone hydrate, thione, monothiohydrate, dithiohydrate, hemiketal, monothioketal hemiketal, dithiohemiketal, ketal, dithioketal, alkenyl, acrylate, methacrylate, acrylamide, sulfone, sulfone, amine, hydrazide, thiol, disulfide, thiol hydrate, carboxylic acid, isocyanate, isothiocyanate, maleimide, succinimide, benzotriazole, vinylsulfone, chloroethylsulfone, dithiopyridine, vinylpyridine, iodoacetamide, epoxide, glyoxals, diones, mesylates, tosylates, thiosulfonate, tresylate, silane, —(CH 2 ) r CO 2 H, —(CH 2 ) r′ CO 2 NS, —(CH 2 ) r′ CO 2 Bt, —(CH 2 ) r CH(OR) 2 , —(CH 2 ) r CHO, —(CH 2 ) 2 —N H 2 , —(CH 2 ) r M, —(CH 2 ) r —S—SO 2 —R, where r is 1-5, r′ is 0-5, R is aryl or alkyl, NS is N-succinimidyl, Bt is 1-benzotriazolyl, and M is N-maleimidyl, and protected and activated forms of any of the foregoing.

11. The method of claim 1 , wherein the polymeric reagent has the following structure:

wherein (m) is 2 to 4000 and each of X 7 , X 8 , Z, (g′), (j) and h is as previously defined.

12. The method of claim 1 , wherein the polymeric reagent has the following structure:

wherein (m) is 2 to 4000, and (f) is 0 to 6 and (n) is 0 to 20.

13. The method of claim 1 , wherein the polymeric reagent has a structure selected from the group consisting of

wherein each (m) is 2 to 4000.

14. The method of claim 1 , wherein the polymeric reagent has a structure selected from the group consisting of:

wherein each (m) is 2 to 4000.

15. The method of claim 1 , wherein the polymeric reagent has a structure selected from the group consisting of:

16. The method of claim 1 , wherein the polymeric reagent has a structure selected from the group consisting of:

wherein each (m) is 2 to 4000 and each (n) 0 to 20.

17. The method of claim 1 , wherein the active agent is a protein.

18. The method of claim 1 , wherein the active agent is selected from the group consisting of erythropoietin, granulocyte-colony stimulating factor, interferon-α, human growth hormone, interferon-β, follicle stimulating hormone, Factor VIII, B-domain deleted Factor VIII, desmopressin and amdoxivir.