• Cefixime trihydrate packaged and labeled.

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SKU: C051

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Cefixime trihydrate is a broad-spectrum third generation cephalosporin targeting a wide range of Gram-positive and Gram-negative organisms. Cefixime trihydrate is especially useful against pathogens responsible for respiratory tract infections such as Haemophilus influenzae and Moraxella catarrhalis.

    CAS Number

    125110-14-7 (trihydrate); 79350-37-1 (anhydrous)

    Molecular Formula

    C16H15N5O7S2 • 3 H2O

    Molecular Weight


    Mechanism of Action

    Like β-lactams, cephalosporins interfere with PBP (penicillin binding protein) activity involved in the final phase of peptidoglycan synthesis. PBP’s are enzymes which catalyze a pentaglycine crosslink between alanine and lysine residues providing additional strength to the cell wall. Without a pentaglycine crosslink, the integrity of the cell wall is severely compromised and ultimately leads to cell lysis and death. Resistance to cephalosporins is commonly due to cells containing plasmid encoded β-lactamases. Cefixime however, is resistant to many β-lactamases encoded by β-lactam resistant strains.

    Storage Conditions


    Tariff Code



    Effective against Gram-positive and Gram-negative bacteria.


    Eukaryotic Cell Culture Applications

    Using Caco-2 human intestinal epithelial cell line expressing intestinal peptide transporter (PEPT1), uptake of the anionic β-lactam Cefixime was studied.  Researchers found that alterations of Ca2+ by Ca2+ channel blockers affect the pH of regulatory systems like apical Na+ and H+ exchange and alter the H+ gradient, which is the driving for uptake into epithelial cells.  For example, at a surface pH of ≥ 6.25, the predominant fraction of cefixime is charged, and thus shows only very low levels of interaction with PEPT1.  The addition of the calcium blocker Nifedipine reduces the intracellular acidification induced by the influx of cefixime and maintained a higher electrochemical proton gradient across the apical plasma membrane, allowing higher transport rates (Wenzel et al, 2002). 

     Flavonoids from plants were able to alter the transport of cefixime via PEPT1 in Caco-2 cells.  Of the 33 flavonoids tested, quercetin, genistein, naringin, diosmin, acacetin, and chrysin increased cefixime uptake by up to 60% via activating apical Na+/H+ exchange (Wenzel et al, 2001).

    Microbiology Applications

    Cefixime trihydrate is commonly used in clinical in vitromicrobiological 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 for infected patients. Representative MIC values include:

    • Haemophilus influenzae 0.008 µg/mL – 2 µg/mL
    • Moraxella catarrhalis 0.06 µg/mL – 0.5 µg/mL
    • For a complete list of Cefixime MIC values, click here.

    Media Supplements

    Cefixime can be used as a selective agent in several types of isolation media:

    Sorbitol Macconkey Agar - Cefixime-Tellurite Supplement

    mTSB - VCC Selective Supplement

    CR-SMAC - Cefixime Supplement





    Light yellow crystalline powder



    Water Content (Karl Fischer)




    Optical Rotation

    -75° to -88°


    (On Dried Basis): 950-1030 µg/mg


    Chromatographic Purity:
    Individual Impurity: ≤1.0%
    Total Impurities: ≤2.0%



    Wenzel U, Kuntz S, Diestel S and Daniel H (2002)  PEPT1-mediated cefixime uptake into uman intestinal epithelial cells is increased by Ca2+ channel blockers.  Antimicrob. Agents. Chemother. 46(5):1375-1380

    Wenzel U, Kuntz S and Daniel H (2001)  Flavonoids with epidermal growth factor-receptor tyrosine kinase inhibitory activity stimulate PEPT1-mediated cefixime uptake into human intestinal epithelial cells. J. Pharmacol. Exp. Ther. 299(1):351-357  PMID  11561098

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