• Metronidazole packaged and labeled.

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SKU: M011

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Metronidazole is a bioactive small molecule and broad-spectrum nitromidazole antibiotic used against anaerobic bacteria and parasites. The hydroxy metabolite, 1-(2-hydroxy-ethyl)-2-hydroxy methyl-5-nitroimidazole is considered the major active metabolite from the 5 metabolites produced in vivo.

Metronidazole is sparingly soluble in aqueous solution. 

    CAS Number


    Molecular Formula


    Molecular Weight

    171.15 g/mol

    Mechanism of Action

    Metronidazole has a unique mode of action, its metabolites forming unstable molecules which are incorporated into cellular DNA, and inhibit DNA replication and transcription. This mechanism has a bactericidal effect on anaerobic cell-encoded β-lactamases.  It has shown activity against the majority of obligate anaerobes, but did not demonstrate significant in vitro activity against facultative anaerobes or obligate aerobes.

    Storage Conditions

    2-8°C; Protect from light

    Tariff Code



    Metronidazole is mostly used to combat anaerobic Gram-positive and Gram-negative bacteria including Clostridium difficile and Bacteroides fragilis. It can also be used for parasites like Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis.


    Eukaryotic Cell Culture Applications

    Metronidazole cytotoxicity was assessed in human dental pulp stem cells (hDPSCs) when it was mixed with a polydioxanone polymer solution (PDS) and processed into bioactive nanofibrous scaffolds. Research suggests that these scaffolds could be a biologically safe antimicrobial delivery system for regenerative endodontics (Bottino et al, 20130).

    Microbiology Applications

    The effect of Metronidazole, along with gentamicin and vancomycin, was evaluated in the gut microbiome of the T-bet−/−Rag2−/−  ulcerative colitis (TRUC) mouse mode.  This model is useful for studying gut microbiome contributions to colonic inflammatory pathogenesis under disease state and treatment-induced remission and reviewing the microbes and microbial pathways involved in IBD and host-microbiota responses, offering the potential for therapeutic manipulation of the gut microbiome in colitis (Rooks et al, 2014).

    Metronidazole is commonly used in clinical in vitro microbiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram-positive and Gram-negative anaerobic microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options . Representative MIC values include:

      • Clostridium difficile 0.25 µg/mL – 0.5 µg/mL
      • Bacteroides fragilis 0.125 µg/mL -1 µg/mL
      • For a complete list of Metronidazole MIC values, click here.





    White or yellowish crystalline powder



    Impurity Profile

    Any impurity: Not more than 0.1%
    Total impurities: Not more than 0.2%

    Melting Point


    Loss on Drying


    Sulfated Ash

    Not more than 0.1%

    Heavy Metals

    Not more than 20ppm

    Residual Solvents

    Methylene oxide: Not more than 0.15 ppm
    Formic acid: Not more than 124 ppm



    Bottino MC et al (2013)   Bioactive nanofibrous scaffolds for regenerative endodontics. J. Dent. Res.  92(11):963-969  PMID 24056225

    Lofmark S, Edlund C and Nord CE (2010)  Metronidazole Is still the drug of choice for treatment of anaerobic infections. Clin. Infect. Dis. 50 Suppl 1:S16-23

    Rooks et al (2014)  Gut microbiome composition and function in experimental colitis during active disease and treatment-induced remission. ISME J 8(7):1403-1417  PMID 24500617

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