Simultaneous determination of the intravenous and oral pharmacokinetic parameters of D,L-verapamil using stable isotope-labelled verapamil

Eur J Clin Pharmacol. 1981 Jan;19(2):133-7. doi: 10.1007/BF00568400.


Following i.v. administration, the plasma concentration-time curve of verapamil could best be described by either a mono- or biexponential equation. Total plasma clearance (1.26 1/min) approached liver blood flow (1.51/min), so it can be concluded that its clearance is liver blood flow-dependent. Although absorption was almost complete after oral administration, absolute bioavailability (20%) was low, due to extensive hepatic first-pass metabolism. The approach using stable isotope-labelled and unlabelled drug permits simultaneous administration by the intravascular and extravascular routes, thus allowing determination of absolute bioavailability in a single experiment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Biological Availability
  • Deuterium
  • Female
  • Humans
  • Injections, Intravenous
  • Kinetics
  • Liver / metabolism
  • Male
  • Verapamil / administration & dosage
  • Verapamil / metabolism*


  • Deuterium
  • Verapamil