title: Study of the metabolism of spiramycin in pig liver.
abstract: A major metabolic pathway of spiramycins in pig liver is described. This biochemical reaction involves L-cysteine--a common amino acid present in most animal tissues--which reacts with the aldehyde function of the antibiotic forming a thiazolidine ring. This transformation of spiramycin derivatives drastically increased their polarity. A preliminary HPLC method enabling the quantitation of each metabolite in the range 0.5 microg/g of liver tissue is proposed. Spiramycin S is used as an internal standard while extraction procedures take into account the physico-chemical properties of the thiazolidine moieties. By comparison, previous HPLC methods underestimated the exact amount of antibiotic residues because these metabolites were not extracted from the studied tissues.
authors.affiliation: Rhône Poulenc Rorer, Centre de Recherche de Vitry Alfortville, Vitry sur Seine, France.
authors.forename: P
authors.initials: P
authors.lastname: Mourier
authors.forename: A
authors.initials: A
authors.lastname: Brun
mesh_terms: D000097:Acetonitriles; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003500:Cyclization; D003545:Cysteine / Q000737:chemistry; D005188:False Negative Reactions; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D015572:Spiramycin / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D013552:Swine; D013844:Thiazoles / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000900:Anti-Bacterial Agents; D013844:Thiazoles; D015572:Spiramycin; D003545:Cysteine; C032159:acetonitrile