The instant invention relates to novel prodrugs of optically pure benzoquinolizine-2-carboxylic acid and pharmaceutical compositions that include the prodrugs. In particular, the present invention relates to the sulfonic acid salts of L-alanine and L-valine prodrugs of S-(&minus；)-9-fluoro-6,7-dihydro-8-(4-hydroxypiperidin-1-yl)-5-methyl-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acid. The compounds and compositions of the invention can be used to treat bacterial Gram-positive, Gram-negative and anaerobic infections, especially infections caused by resistant Gram-positive organism and Gram-negative organism, mycobacterial infections and emerging nosocomial pathogen infections.
