Patent ID: 7279458

Claim:
A compound of the formula: or a pharmaceutically-acceptable salt thereof; wherein each of X 1 and X 2 is independently hydrogen or chloro; W is N or CCl; R 1 and R 2 are independently selected from hydrogen and C 1-6 alkyl; each R 3 is independently selected from C 1-6 alkyl, OR, halo, —SR, —S(O)R, —S(O) 2 R, and —S(O) 2 OR, where each R is independently C 1-6 alkyl optionally substituted with COOH or 1 to 3 fluoro substituents; one of R 4 and R 5 is hydroxy and the other is hydrogen; R 6 and R 7 are independently hydrogen or methyl; R 8 is hydrogen or a group of the formula: R 9 is selected from hydrogen, C 1-6 alkyl and C 3-6 cycloalkyl, where alkyl and cycloalkyl are optionally substituted with —COOH or 1 to 3 fluoro substituents; R b is hydrogen, methyl or ethyl; R c is C 2-12 alkylene, where the alkylene group is optionally substituted with —COOH; n is an integer from 0 to 3; x is 0 or 1; y is 0 or 1; and the pyridinium ring is attached to the methylene group at the meta or para position.