Effect of pirenzepine on theN‐demethylation of D(−)ephedrine and ethylmorphine by rabbit liver microsomes

摘要

AbstractThe possible interaction of pirenzepine with the mixed‐function oxidases obtained from phenobarbital‐pretreated rabbit microsomes was examinedin vitro. Under experimental conditions that did not lead to its ownN‐demethylation, the drug inhibited the microsomal oxidase systems responsible for theN‐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 hepaticN‐demethylating system is not a result of low affinity of the drug to