Description
Vancomycin and Teicoplanin are natural antibiotic drugs belonging to the chemical class of glycopeptides. This is a very usefull class of drugs, clinically used especially as last resort in drugs resistant infections.
Vancomycin is produced by Streptomyces Orientalis, while Teicoplanin is produced by Actinoplanes teichomyetius.
Both the molecules have a complex structure: they show a peptide portion with L and D-aminoacids (these are not present in human cells), chlorinated aromatic amino acids, ether functions.
Pharmacokinetics, clinical use and toxicity
According to their high molecular weight this drugs are not administrable orally (via OS) to treat systemic infections (they are not absorbed in the intestine). Therefore they can be administered either by mouth to treat infections of the gastroenteric tract (e.g. caused by Clostridium Difficile) or by slow intravenous administration (Vancomycin) or intramuscular (teicoplanin) above all to treat infections provoked by methicillin resistant Gram positive cocci (MRSA).
Vancomycin half-life → 6h binding to plasma proteins → 30% It requires injections every 12h
Teicoplanin half-life → 40h binding to plasma proteins → 95% It requires injections every 24h
They are both eliminated with urine.
Side-effects: Phlebitis (pain and inflammation at the site of injection), ototoxicity, nefrotoxicity.
Pharmacodynamics (mechanism of action)
They act on the cell wall biogenesis but differently from fosfomycin, D-cycloserine and β-lactam antibiotics. They performs their antibiotic action through the bond (non covalent) with the fragment acyl D-alanine D-alanine, interfering with transglycosylation (the union of two monomers NAG-NAM-pentapeptide, the building blocks of peptidoglycan) and transpeptidation (the formation of crossed bonds between two peptidic portions).
The resulting effect is BACTERICIDAL. The spectrum includes aerobic Gram+, anaerobics.
