Patent ID: 8263062

Claim:
A multi-arm polymer prodrug having the structure: wherein: R is an organic radical possessing from 3 to 25 carbon atoms; X is a spacer having an atom length of from 4 atoms to 50 atoms possessing the structure Y—Z, where Y has the structure —(CH 2 ) a —C(O)NH—(CH 2 ) b —(CH 2 CH 2 O) c — and Z is either —C(O)—O— or —O—C(O)—O—; where a is selected from 1, 2, 3, and 4; b is selected from 1, 2, 3, and 4; c ranges from 0 to 10; n ranges from 5 to 400; D is a camptothecin attached at its 10-, 11- or 20-ring position; and q has a value from 3 to 25.