title: Interaction of chlormezanone with rat liver microsomes and its degradation.
abstract: Chlormezanone binds to oxidized cytochrome P450 in rat liver microsomes with a binding curve according to type I like hexobarbital but less pronounced and with a general shift to the left. Ethylmorphine N-demethylation, ethoxycoumarin and ethoxyresorufin O-deethylation are inhibited by chlormezanone in mM concentrations only whereas pentoxyresorufin O-depentylation is inhibited by about 50% in microM concentrations. Luminol and lucigenin amplified chemiluminescence indicating the formation of reactive oxygen species was not influenced in concentration ranges between mM and microM, whereas NADPH/Fe stimulated lipid peroxidation showed a tendency of inhibition. But scavenger activity could not be demonstrated: the zymosan stimulated chemiluminescence of whole blood was not influenced significantly. The degradation process of chlormezanone was elucidated. The first step involves ring opening by chemical hydrolysis with subsequent formation of an unstable acylhalfaminal which is the source of 4-chlorobenzaldehyde. This aldehyde undergoes enzymatically controlled oxidation to 4-chlorobenzoic acid which is the parent compound of following phase II reactions. The second degradation product is 2-carboxyethane-sulfinic-acid-N-methylamide, which is hydrolyzed very quickly. Neither oxidation of the sulfinic acid or its N-methylamide derivative could be observed nor N-demethylation of chlormezanone.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Friedrich-Schiller-Universität, Jena, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Klinger
authors.forename: H
authors.initials: H
authors.lastname: Oelschläger
authors.forename: E
authors.initials: E
authors.lastname: Karge
authors.forename: D
authors.initials: D
authors.lastname: Rothley
mesh_terms: D000818:Animals; D001711:Biotransformation; D002720:Chlormezanone / Q000378:metabolism* / Q000494:pharmacology*; D003374:Coumarins / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004347:Drug Interactions; D005036:Ethylmorphine / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008163:Luminescent Measurements; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D009125:Muscle Relaxants, Central / Q000378:metabolism* / Q000494:pharmacology*; D010078:Oxazines / Q000378:metabolism; D010105:Oxygenases / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D013268:Stimulation, Chemical; D015054:Zymosan / Q000494:pharmacology
chemical_list: D003374:Coumarins; D065607:Cytochrome P-450 Enzyme Inhibitors; D009125:Muscle Relaxants, Central; D010078:Oxazines; D017382:Reactive Oxygen Species; C017299:7-ethoxycoumarin; C007649:ethoxyresorufin; C044943:pentoxyresorufin; D015054:Zymosan; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D002720:Chlormezanone; D005036:Ethylmorphine