Ornidazole-d5 (Synonyms: (±)-Ornidazole-d5)

Ornidazole-d₅ is intended for use as an internal standard for the quantification of ornidazole by GC- or LC-MS. Ornidazole is an orally bioavailable 5-nitroimidazole derivative with antibacterial and antiprotozoal activities.^1,2 Ornidazole inhibits the growth of clinical isolates of B. fragilis (MICs = 0.5-5 μM) and various anaerobic bacteria when used at concentrations ranging from less than 0.1 to 3.2 μg/ml.^2,3 It also inhibits the growth of Giardia isolates (IC₅₀s = 0.01-0.47 μg/ml).⁴ Oral administration of ornidazole reduces T. vaginalis and T. foetus infection in mice and E. histolytica infection in rats with curative dose (CD₅₀) values of 37, 3, and 10 mg/kg, respectively.¹ Ornidazole (400 mg/kg per day) induces infertility in male rats within 7 days and inhibits spermatozoa binding to rat oocyte zona pellucida.^5,6

1.Hoffer, M., and Grunberg, E.Synthesis and antiprotozoal activity of 1-(3-chloro-2-hydroxypropyl)-substituted nitroimidazolesJ. Med. Chem.17(9)1019-1020(1974) 2.Jokipii, L., and Jokipii, A.M.Comparative evaluation of the 2-methyl-5-nitroimidazole compounds dimetridazole, metronidazole, secnidazole, ornidazole, tinidazole, carnidazole, and panidazole against Bacteroides fragilis and other bacteria of the Bacteroides fragilis groupAntimicrob. Agents Chemother.28(4)561-564(1985) 3.WÜst, J.Susceptibility of anaerobic bacteria to metronidazole, ornidazole, and tinidazole and routine susceptibility testing by standardized methodsAntimicrob. Agents Chemother.11(4)631-637(1977) 4.Majewska, A.C., Kasprzak, W., De Jonckheere, J.F., et al.Heterogeneity in the sensitivity of stocks and clones of Giardia to metronidazole and ornidazoleTrans. R. Soc. Trop. Med. Hyg.85(1)67-69(1991) 5.OberlÄnder, G., Yeung, C.H., and Cooper, T.G.Induction of reversible infertility in male rats by oral ornidazole and its effects on sperm motility and epididymal secretionsJ. Reprod. Fertil.100(2)551-559(1994) 6.Bone, W., Jones, N.G., Kamp, G., et al.Effect of ornidazole on fertility of male rats: Inhibition of a glycolysis-related motility pattern and zona binding required for fertilization in vitroJ. Reprod. Fertil.118(1)127-135(2000)