Norfloxacin-d₅is intended for use as an internal standard for the quantification of norfloxacin by GC- or LC-MS. Norfloxacin is a fluoroquinolone antibiotic that inhibits the growth of Gram-positive and Gram-negative bacteria (MICs = 4 and 1 μg/ml forS. aureusandP. aeruginosa, respectively).¹It also inhibits the growthS. pseudintermedius,S. aureus,E. coli,Pasturella, andS. canisisolates from dogs (mean MIC₅₀s = 0.25, 1, 0.03, 1, and 1 μg/ml, respectively).²Topical administration of norfloxacin (0.1% v/v) reduces corneal ulcer size in a rabbit model ofP. aeruginosacorneal infection. It also prevents encrusted cystitis in bladder and increases survival in a rat model ofCorynebacteriumgroup D2 infection when administered at a dose of 80 mg/kg per day.³Formulations containing norfloxacin have been used to treat urinary tract and gynecological infections.

1.Darrell, R.W., Modak, S.M., and Fox, C.L., Jr.Norfloxacin and silver norfloxacin in the treatment of Pseudomonas corneal ulcer in the rabbit.Trans. Am. Opthalmol. Soc.8275-91(1984) 2.Awji, E.G., Damte, D., Lee, S.-J., et al.The in vitro activity of 15 antimicrobial agents against bacterial isolates from dogsJ. Vet. Med. Sci.74(8)1091-1094(2012) 3.Soriano, F., Rodriguez-Tudela, J.L., Castilla, C., et al.Treatment of encrusted cystitis caused by Corynebacterium group D2 with norfloxacin, ciprofloxacin, and teicoplanin in an experimental model in ratsAntimicrob. Agents Chemother.35(12)2587-2590(1991)