INFLUENCE OF SAMPLE SITE ON BLOOD CONCENTRATIONS OF ICI 35 868

Simultaneous blood samples from an artery, a peripheral veinand a central vein were analysed for ICI 35 868 concentrationsfollowing an induction dose of 2.0 mg kg^–1 administeredi.v. over 60 s, to five patients before cardiac surgery. Upto 60 s after the end of the administration of the drug therewere wide differences in drug concentration between the samplingsites. Thus, any attempt to correlate effect with blood concentrationover this early period would be problematic. From 60 s therewere no significant differences in drug concentration betweenthe three sites. Thus, as long as the mixing period is allowedfor, peripheral venous sampling provides an acceptable alternativeto arterial puncture in studies to correlate drug effect andconcentration and for pharmacokinetic investigations.