Patent ID: 7048925

Claim:
A polymer comprising a recurring unit represented by a formula selected from the group consisting of formula (I) and (II): wherein A comprises at least one acetal group; wherein B is selected from the group consisting of —CH—, —CH(CH 3 )—, CH 2 CH—, —CH 2 C(CH 3 )—, —CH(CH 3 )CH—, and —CHCH(CH 3 )CH(CH 3 )—; wherein Z is selected from the group consisting of C(O)OR 1 , C(O)SR 1 , C(O)NR 1 R 2 , and VU; wherein V is a linker group; wherein U is selected from the group consisting of poly(ethyleneimine), poly(propyleneimine), poly(lysine), PAMAM dendrimer, octaamine dendrimer, hexadecaamine dendrimer, enhancer, and targeting receptor; wherein R 1 and R 2 are each individually selected from the group consisting of hydrogen, C 1 to C 10 alkyl, and C 6 to C 10 aryl; wherein D is a linkage selected from the group consisting of carboxylic amide, carboxylic ester, urea, and urethane; and wherein G is selected from the group consisting of C 4 to C 20 alkyl, C 6 -C 10 aryl, and —(OCH 2 CH 2 ) n —, where n is in the range of 1 to about 250.