Arterial-venous plasma concentration differences of six drugs in the dog and rabbit after intravenous administration.

The arterial blood from the femoral artery and venous blood from the femoral vein wee simultaneously collected following intravenous administration of propranolol, lidocaine, procainamide, furosemide, theophylline and griseofulvin to dogs or rabbits. The preliminary results of arterial-venous (A-V) plasma concentration profiles are reported in this communication. The maximum A/V ratios shortly after a rapid intravenous bolus dose were 277-, 15-, 34-, 33-, 5.4- and 3240-fold, respectively, for the above six drugs. The venous plasma levels were higher than arterial plasma levels during parallel terminal phase by as much as 104, 48, 134, 29, 16, and 47%, respectively, for the above six drugs. These data suggest a very rapid and extensive uptake of the drugs by the sampling tissues (the leg) shortly after dosing. The potential significance of A-V differences in pharmacokinetic and pharmacodynamic studies are briefly discussed.