Name: Thiamphenicol 

Synonyms: thiophenicol, dextrosulphenidol, Win 5063-2, CV8053

Chemical names: D-d-threo-2-dichloroacetamido-1-(4-methylsulfonylphenyl)-1,3-propanediol;

D(+)-threo-1-(4'-methylsulphonylphenyl)-2-dichloroacetamide propane-1, 3-diol;

D-threo-2,2-dichloro-N-b -hydroxy-a-(hydroxymethyl)-p-(methylsulphonyl)-phenethyl acetamide (C.A.S. name)

CAS No.: 15318-45-3

Molecular formula: C12H15Cl2NO5S

Molecular weight: 356.22

Melting point: 164-166°C

Appearance: White crystalline powder

Solubility: Highly soluble in lipids; soluble in dimethylacetamide, dimethylformamide (DMF) and acetonitrile; slightly soluble in absolute ethanol and acetone; practically insoluble in water, ether, ethyl acetate and chloroform.

Stability:

Can be kept for 5 - 6 years when stored in closed containers and protected from humidity and excessive heat.

 

What is thiamphenicol?

Thiamphenicol is an antibiotic active against both Gram-positive and Gram-negative bacteria and particularly effective against anaerobes. It is used for parenteral therapyas the water soluble thiamphenicol glycine hydrochloride and for oral use, as a premix of thiamphenicol base and corn starch. In many countries, thiamphenicol is used as a veterinary antibiotic, especially for the treatment of infectious diseases in cattle, pigs and poultry. In China, Morocco, Italy, and Brazil, it is also for medical uses . In particular, it is used for treating sexually transmitted infections and pelvic inflammatory disease. may be used in the treatment and control of a wide range of respiratory and alimentary tract infections of bacterial origin in calves, pigs and poultry. The oral product is not suitable for the treatment of cattle with functional rumen.

 

Advantages of thiamphenicol over chloramphenicol

As the methyl-sulfonyl analogue of chloramphenicol, thiamphenicol has a similar antibacterial spectrum, and it inhibits protein synthesis in bacteria as chloramphenicol does. However, it excels in several ways.

The main advantage of thiamphenicol over chloramphenicol is that it can be extensively used in human without being associated with aplastic anaemia. 

What’s more, while chloramphenicol is readily metabolized in cattle, poultry, sheep, and humans, most thiamphenicol is excreted in its original form. Specifically, it is excreted both as parent drug and as thiamphenicol glucuronate in pigs and rats.

Moreover, the concentration of thiamphenicol in blood and other body fluids such as bile is higher than chloramphenicol. Relevantly, it is 2.5 to 5 times as effective as chloramphenicol.

 

The antimicrobial activity of thiamphenicol

Thiamphenicol is effective in inhibiting a broad range of microorganisms, and its antibiotic actions work for some species under certain conditions. Relatively low concentrations of thiamphenicol is active against Clostridium, Corynebacterium diphtheriae, Diplococcus pneumoniae, Staphylococcus albus, Streptococcus pyogenes, Streptococcus viridans, Bacteroides, Fusobacterium, Bordatella, Brucella, Haemophilus, Neisseria, Pasteurella, Shigella and some vibrio strains. The bacteria sensitive to moderate concentrations of thiamphenicol include some Bacilli, Erysipelothrix, Staphylococcus aureus and Streptococcus faecalis. To inhibit Listeria, Aerobacter, Escherichia, Klebsiella, Proteus and Salmonellae, relatively high concentrations of thiamphenicol is required.

The thiamphenicol compound is effective against Mycoplasmas, Treponema, Rickettsias, Entamoeba and Actinomycetes. There is no difference between the in vitro antimicrobial activities of the thiamphenicol glycinate ester and that of thiamphenicol base.

 

Dosage

The usual daily dosage of thiamphenicol for calves (not for oral use because of their ruminating attribute) is 30 - 60 mg/kg (30 mg/kg in dairy cows, and for sucking calves 30 mg/kg of body weight), for pigs 20 - 40 mg/kg , and for poultry 15 to 67 mg/kg.

 

Development of thiamphenicol

Thiamphenicol was artificially synthesized by Cutler et al in 1952 in the U.S.. It was then manufactured in the U.S., Italy and Japan successively. From 1980, it was written into British Pharmacopoeia and broadly applied in Europe as a new chemical therapeutic agent. In China, thiamphenicol was used in clinical veterinary in 1990s.

Since the end of 1980s, thiamphenicol was exported to Japan and sold to Taiwan from Mainland China in bulk. Its prices therefore rose continuously and the supply is constantly sufficient.