Mode of action
Once the muramylpentapeptide is formed in the cell cytoplasm, an N-acetylglucosamine unit is added, together with any amino acids needed for the interpeptide bridge of Grampositive organisms. It is then passed to a lipid carrier molecule, which transfers the whole unit across the cell membrane to be added to the growing end of the peptidoglycan macromolecule. Addition of the new building block (transglycosylation) is prevented by teicoplanin which bind to the acyl-d-alanyl-d-alanine tail of the muramylpentapeptide. Because antibiotics are large polar molecules, they cannot penetrate the outer membrane of Gramnegative organisms, which explains their restricted spectrum of activity.
Description
Teicoplanin is a new antibiotic, the second glycopeptide to be developed in over 30 years.
Compared with vancomycin, the only such agent currently available, teicoplanin is
equiefficacious, and has milder side-effects and a longer half-life, allowing once-daily
dosing and bolus injection. Teicoplanin is claimed to have an overall cure rate of 92% in
infections involving skin, joint and bone, endocaditis and septicemia.
Chemical Properties
Yellowish, amorphous powder.
Originator
Merrell Dow (Italy)
Uses
anticonvulsant, antipsychotic
Uses
Teicoplanin complex is family of closely related metabolites produced by Actinoplanes teichomyceticus. Teicoplanin complex possesses potent broad spectrum antibiotic activity against Gram positive bacteria, including MRSA and E. faecalis. The metabolites share a common glycopeptide core (teicoplanin A-3) on which a family of fatty acids varying in length, degree of saturation and branching are linked as amides through one of the aminoglycoside moieties. The major component of the complex is teicoplanin A2 which itself has five major components (teicoplanin A2-1 to A2-5) and four minor components (teicoplanin RS-1 to RS-4).
General Description
Teicoplanin (Teichomycin A2, Targocid) is a mixture offive closely related glycopeptide antibiotics produced bythe actinomycete Actinoplanes teichomyceticus. The teicoplanin factors differ only in the acyl group inthe northernmost of two glucosamines glycosidicallylinked to the cyclic peptide aglycone. Another sugar, Dmannose,is common to all of the teicoplanins. Thestructures of the teicoplanin factors were determined independentlyby a combination of chemical degradationand spectroscopic methods in three different groupsin 1984.
The teicoplanin complex is similar to vancomycin structurallyand microbiologically but has unique physical propertiesthat contribute some potentially useful advantages.While retaining excellent water solubility, teicoplanin has significantlygreater lipid solubility than vancomycin. Thus, teicoplaninis distributed rapidly into tissues and penetratesphagocytes well. The complex has a long elimination halflife,ranging from 40 to 70 hours, resulting from a combinationof slow tissue release and a high fraction of protein bindingin the plasma (～90%). Unlike vancomycin, teicoplanin isnot irritating to tissues and may be administered by intramuscularor intravenous injection. Because of its long half-life, teicoplaninmay be administered on a once-a-day dosing schedule.Orally administered teicoplanin is not absorbedsignificantly and is recovered 40% unchanged in the feces.
Teicoplanin exhibits excellent antibacterial activity againstGram-positive organisms, including staphylococci, streptococci,enterococci, Clostridium and Corynebacterium spp.,Propionibacterium acnes, and L. monocytogenes. It is not activeagainst Gram-negative organisms, including Neisseriaand Mycobacterium spp. Teicoplanin impairs bacterial cellwall synthesis by complexing with the terminal D-alanine-Dalaninedipeptide of the peptidoglycan, thus preventing crosslinkingin a manner entirely analogous to the action ofvancomycin.
Clinical Use
Antibacterial agent.
Metabolism
Teicoplanin is excreted almost entirely by glomerular
filtration in the urine, as unchanged drug. Two
metabolites are formed probably by hydroxylation and
represents 2-3% of the administered dose. Unchanged
teicoplanin is mainly excreted by the urinary route while
2.7% of the administered dose is recovered in feces (via
bile excretion) within 8 days following administration.
