| US 7,569,214 B2 | ||
| Method for preparing water-soluble polymer derivatives bearing a terminal carboxylic acid | ||
| Antoni Kozlowski, Huntsville, Ala. (US) | ||
| Assigned to Nektar Therapeutics AL, Corporation, Huntsville, Ala. (US) | ||
| Filed on Sep. 09, 2003, as Appl. No. 10/659,735. | ||
| Claims priority of provisional application 60/409348, filed on Sep. 09, 2002. | ||
| Prior Publication US 2005/0036978 A1, Feb. 17, 2005 | ||
| Int. Cl. A61K 31/74 (2006.01); A61K 47/48 (2006.01) | ||
| U.S. Cl. 424—78.17 [424/78.31] | 19 Claims |
1. A polymer having the following structure:
 POLY is a water-soluble polymer segment having a nominal average molecular weight of from about 2,000 daltons to about 25,000
daltons;
(a) is either zero or one;
X, when present, is a spacer moiety;
(z) is an integer from 1 to 24;
R1, in each occurrence, is in dependently H or an organic radical selected from the group consisting of alkyl, substituted alkyl,
alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, and substituted aryl;
R2, in each occurrence, 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; and
each R4 is a either (i) an organic radical independently selected from the group consisting of alkyl, substituted alkyl, alkenyl,
substituted alkenyl, alkynyl, substituted alkynyl, aryl, and substituted aryl, or (ii) one or more atoms that combine with
another R4 or the remaining R4 moieties to form a cyclic ortho ester structure.
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