| 摘要 |
Stability of biocompatible polymers of the formula (I): wherein Z is -C(O)R1; each R1 is independently selected from a linear, branched, or cyclic alkyl, alkoxy, or aryl with 1 to 18 carbon atoms optionally substituted by carbonyl, oxy, thio, and/or nitrogen; each R2 is independently selected from hydrogen or a linear or branched hydrocarbon with 1 to 4 carbon atoms; X is selected from the group consisting of -OR1, -SR1, -N(R1)2 and divalent or trivalent headgroups terminated in oxygen, nitrogen, or sulfur; y is greater than or equal to 1 and less than or equal to 3; is enhanced by providing compositions where there is a low level of -OH end group impurity, i.e., where Z is -H instead of -C(O) R1and/or X is -OH instead of -OR1, -SR1, -N(R1)2 or divalent or trivalent headgroups terminated in -O-, -N-, or -S-, such that there are no more than 10 of these -OH end groups for every 100 intended biocompatible polymer molecules. |
