title: Effect of pirenzepine on the N-demethylation of D(-)ephedrine and ethylmorphine by rabbit liver microsomes.
abstract: The possible interaction of pirenzepine with the mixed-function oxidases obtained from phenobarbital-pretreated rabbit microsomes was examined in vitro. Under experimental conditions that did not lead to its own N-demethylation, the drug inhibited the microsomal oxidase systems responsible for the N-demethylation of D(-)ephedrine and ethylmorphine. Kinetic studies showed that pirenzepine inhibited the metabolism of both drugs in a competitive manner. The results indicated that the observed pirenzepine stability to the hepatic N-demethylating system is not a result of low affinity of the drug to the system.
authors: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors: H A
authors: HA
authors: el-Obeid
authors: K A
authors: KA
authors: al-Rashood
authors: H A
authors: HA
authors: al-Khamees
authors: K I
authors: KI
authors: al-Khamis
authors: M S
authors: MS
authors: Mian
mesh_terms: D000818:Animals; D003640:Dealkylation; D003864:Depression, Chemical; D004809:Ephedrine / Q000493:pharmacokinetics*; D005036:Ethylmorphine / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D010890:Pirenzepine; D006899:Mixed Function Oxygenases; D004809:Ephedrine; D005036:Ethylmorphine; D010634:Phenobarbital