Chloramphenicol

April 27, 2020
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Chloramphenicol is a venerable antibiotic that was isolated from the soil bacterium Streptomyces venezuelae in the late 1940s by researchers at Parke–Davis (Detroit), the University of Illinois (Urbana–Champaign), and Yale University (New Haven, CT). It was originally called chloromycetin.

In July 1949, the Parke–Davis team published the structure of the compound, which then was given the generic name chloramphenicol; Parke–Davis adopted Chloromycetin as its trade name. The group simultaneously announced a laboratory synthesis of chloramphenicol. It was the first totally synthetic antibiotic.

Over the years, chloramphenicol has been used to treat conjunctivitis, meningitis, cholera, and typhoid fever. It is active against bacteria such as Escherichia coli, Staphylococcus spp., and Salmonella spp.

Chloramphenicol can produce some serious adverse effects, including aplastic anemia, neurotoxicity, and some cancers. In 1991, the United States discontinued the use of the oral formulation because of its association with aplastic anemia. In 2007, the World Health Organization classified it as a probable human carcinogen.

Chloramphenicol is still being used in the United States and other countries as an injectable. It is administered intravenously as the more water-soluble prodrug chloramphenicol monosuccinate. Intravenous dosages are greater than oral ones because much of the ester is eliminated before the body can hydrolyze it. Another prodrug, chloramphenicol palmitate, is given orally, but like the parent compound, it is no longer approved for use in the United States.

Chloramphenicol hazard information

Hazard class* Hazard statement
Carcinogenicity, category 2 H351—Suspected of causing cancer Chemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

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Chloramphenicol fast facts

CAS Reg. No. 56-75-7
SciFinder
nomenclature
Acetamide, 2, 2-dichloro-N-[(1R,2R)-2-hydroxy-1-(hydroxymethyl)-2-(4-nitrophenyl)ethyl]-
Empirical formula C11H12Cl2N2O5
Molar mass 323.13 g/mol
Appearance White to pale yellow needles, plates, or powder
Melting point 150.5–151.5 ºC
Water solubility 2.5 g/L
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