VERAPAMIL IMPURITY J

Calcium channel blocker
P-glycoprotein (P-gp) inhibitor

Norverapamil ((±)-Norverapamil) is similarly effective as verapamil at inhibiting isoniazid and rifampicin tolerance and killing of intracellular M. tuberculosis in the absence of other drugs. norverapamil, also inhibits macrophage-induced tolerance and achieves similar serum levels to verapamil.
Verapamil and its major metabolite Norverapamil were identified to be both mechanism-based inhibitors and substrates of CYP3A and reported to have non-linear pharmacokinetics in clinic.

Norverapamil (9 mg/kg; p.o.), a major metabolite of verapamil, has terminal half-life, AUC and Cmax values of 9.4 hours, 260 ng▪h/ml, and 41.6 ng/mL, respectively.