Chloramphenicol, USP

- Overview
  - Chloramphenicol, USP is a broad-spectrum bacteriostatic antimicrobial that inhibits bacterial protein synthesis. Originally derived from Streptomyces venezuelae, Chloramphenicol is a synthetic antibiotic that is effective against a wide variety of Gram-positive and Gram-negative bacteria.
    Chloramphenicol, USP is soluble in ethanol but sparingly soluble in water.
    Chloramphenicol, USP conforms to United States Pharmacopoeia specifications.
    
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    Background
    
    After entering a bacterial cell, Chloramphenicol reversibly binds to the peptidyltransferase center at the 50S ribosomal subunit of 70S ribosome, preventing peptide bond formation. Resistance to Chloramphenicol may be due to decreased cell permeability or a mutation in the 50S ribosomal subunit.
- Properties
  - CAS Number
    
    56-75-7
    
    Molecular Formula
    
    C11H12Cl2N2O5
    
    Molecular Weight
    
    323.13
    
    Appearance
    
    White to greyish-white or yellowish-white, needle-like crystals or elongated plates
    
    Solubility
    
    Soluble in ethanol (50 mg/ml). Sparingly soluble in water (2.5 mg/ml)
    
    Other Properties
    
    Source: Streptomyces venezuelae
    PH: 4.5 - 7.5
    Melting Point: 149°C - 153°C
    Optical Rotation: +17.0º to +20.0º
    Purity Level: 97.0%-103.0%
    
    Storage
    
    2-8 °C. Store protected from light
    
    * For research use only
- Applications
  - Application Description
    
    Spectrum: Chloramphenicol is effective against Gram-positive and Gram-negative bacteria, both aerobic and anaerobic bacteria. It is also effective against Mycoplasmas, Chlamydiae, and rickettsiae.
    
    Microbiology Applications: Chloramphenicol 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:
    Neisseria meningitides 0.06 µg/mL - 8 µg/mL
    Streptococcus pneumoniae 0.25 µg/mL – 4 µg/mL
    
    Bacterial resistance to Chloramphenicol is enzymatic inactivation by acetylation via different types of Chloramphenicol acetyltransferases (CATs), and this feature has been exploited for gene selection. Chloramphenicol is routinely used to select for transformed cells that express the Chloramphenicol resistance gene, cat.Media Supplement
    Chloramphenicol is used as a selective agent in:
    Dermasel Agar - Dermasel Selective Supplement. For selection of dermatophyte fungi from hair, nails, and skin scrapings.
    Chromogenic Candida Agar - Candida Selective Supplement
    
    Plant Biology Applications: Chloramphenicol be used in plant transformation studies, and by inserting the gene of interest along with the Chloramphenicol resistant gene (cat), one can select for transformed plants.
    Chimeric genes made up of the nopaline synthase promoter and bacterial coding sequences that specify resistance to Chloramphenicol were inserted into a Ti plasmid vector and used to transform tobacco protoplasts. The use of a non-oncogenic Ti plasmid was used and phenotypically normal fertile plants regenerated from the resistant calli, thus providing a natural environment for studying gene expression and development of plant cells (De Bloc et al, 1984).
    
    Cancer Applications: Researchers at the University of Manchester, UK found a conserved phenotypic dependence on the biogenesis of mitochondria for the expansion of cancer stem cells. Since Chroramphenicol can inhibit mitochrondrial biogenesis, it was found to inhibit tumor-sphere formation in MCF7 cells. This approach is mutation-independent, and treats cancer like a single disease of ‘stemness’, independent of tumor type. This approach was successful in vitro with 12 different cancer cell lines, across 8 different tumor types (breast, DCIS, ovarian, prostate, lung, pancreatic, melanoma, and glioblastoma (brain) (Lamb et al, 2015).