A study of metabolites isolated from the urine samples of cats and dogs administered orbifloxacin.

Urine samples of cats and dogs collected for 24 hr after a subcutaneous injection of orbifloxacin (OBFX) were analyzed. The metabolites were examined using HPLC. In the dog urine, 87% of total was the parent compound and 13% glucuronide compound of OBFX and 96% was parent and 4% metabolite in the cat urine. The metabolite of cat urine was identified as N-hydroxy OBFX, determined by comparison of the extraction of urine with chloroform with the standard compound of N-hydroxy OBFX, using LC/APCIMS. N-hydroxy OBFX had a weaker antibacterial activity against fluoroquinolone sensitive bacteria than the parent compound.