• Florfenicol packaged and labeled.

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SKU: F002

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Florfenicol is a fluorinated synthetic analog of Thiamphenicol, belonging to the amphenicol class which also contains Choramphenicol.  It is metabolized to Florfenicol Amine.  It is a highly potent inhibitor of bacterial protein synthesis and has primarily bacteriostatic activity.  It is used in animal research applications against to combat bacterial infections, and to promote animal growth in aquaculture.  Florfenicol is soluble in DMSO and DMF, but sparingly soluble in aqueous buffers. 

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  • Florfenicol Amine (F027)

    CAS Number


    Molecular Formula


    Molecular Weight


    Mechanism of Action

    After entering a bacterial cell, Florfenicol binds to the 50S ribosomal subunit preventing peptide bond formation. Resistance to Florphenicol may be due to decreased cell permeability or a mutation in the 50S ribosomal subunit.

    Storage Conditions


    Tariff Code



    Florfenicol is a broad-spectrum antibiotic targeting a wide variety of Gram-positive and Gram-negative bacteria, especially those causing bovine respiratory infections such as bovine respiratory disease (Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni). It can also be used for the bacteria causing enteric septicemia in catfish.


    Eukaryotic Cell Culture Applications

    Florfenicol was found to show immunosuppressive activity on mouse splenocytes that were harvested to assess lymphocyte proliferation of CD3+T and CD19+B lymphocytes.  The compound suppressed splenocyte proliferation, demonstrating that it could suppress humoral and cellular immune responses in mice.  (Shuang et al, 2011).

    Microbiology Applications

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

    • Haemophilus parasuis 0.24 µg/mL – 4 µg/mL
    • Escherichia coli 0.5 µg/mL – 128 µg/mL
    • For a representative list of fForfenicol MIC values, click here.
    The first Florfenicol resistance gene (pp-flo) was found in a fish pathogen.  Plasmid-mediated florfenicol resistance is encoded by the floR gene in E. coli (Cloeckaert et al, 2000).   





    White crystalline powder


    Derivative of Thiamphenicol



    Melting Point


    Optical Rotation

    -16° to -19°


    (On Dried Basis): ≥98.0%

    Loss on Drying




    Cloeckaert A et al (2000)  Plasmid-mediated Florfenicol resistance encoded by the floR gene in Escherichia coli isolated from cattle. Antimicrob. Agents. Chemother. 44(10):2858-2860 

    Liu Y et al (2018)  Relevance of breast cancer resistance protein to pharmacokinetics of florfenicol in chickens: A perspective from in vivo and in vitro studies. Int. J. Mol. Sci. 19(10):3165 PMID 30326566

    Schwarz S, Kehrenberg C, Doublet B, and Cloeckaert A (2004) Molecular basis of bacterial resistance to chloramphenicol and florfenicol. FEMS Microbiol Rev. 28(5):519-542  PMID 15539072

    Shuang G et al (2011)  Immunosuppressive activity of Florfenicol on the immune responses in mice. Immunol. Invest. 40(4):356-366. 

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