• Cephalexin hydrate packaged and labeled.

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SKU: C024

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Description

Cephalexin Hydrate is a broad-spectrum, first-generation cephalosporin that interferes wtih bacterial peptidoglycan synthesis.   It is slightly soluble in aqueous solution.

    CAS Number

    23325-78-2

    Molecular Formula

    C16H17N3O4S · H2O

    Molecular Weight

    347.39 g/mol (anhydrous basis)
    365.41 g/mol (monohydrate)

    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.

    Storage Conditions

    -20°C (protect from light)

    Tariff Code

    2941.90.3000

    Spectrum

    Cephalexin hydrate is a broad-spectrum antibiotic targeting a wide variety of Gram-positive and Gram-negative bacteria especially those which cause respiratory infections.

Applications

    Microbiology Applications

    Cephalexin hydrate 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 for infected patients. Representative MIC values include:

    • Streptococcus pyogenes 0.2 µg/mL – 12.5 µg/mL
    • Streptococcus pneumoniae 0.78 µg/mL – 3.12 µg/mL
    • For a complete list of Cephalexin MIC values, click here.

    In vitro degradation of Cephalexin monohydrate and its effect on MIC and MBC was studied using the broth microdilution method.  Cephalexin was among the most degraded compounds tested, which has implications for determination of MIC  for slow-growing bacteria (Lallemand et al, 2016).

Specifications

    Form

    Powder

    Appearance

    White or almost white crystalline powder

    Source

    Semi-synthetic

    Water Content (Karl Fischer)

    4.0-8.0%

    pH

    3.0-5.5

    Optical Rotation

    +149° to +158°

    Assay

    950-1030 µg/mg

References

    References

    Georgopapadakou NH (1992) Mechanisms of action of cephalosporin 3'-quinolone esters, carbamates, and tertiary amines in Escherichia coli. Antimicrob. Agents Chemother. 37(3):559-565

    Lallemand EA et al (2016) In vitro degradation of antimicrobials during use of broth microdilution method can increase the measured minimal inhibitory and minimal bactericidal concentrations. Front Microbiol. 7:2051 PMID 28066372

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