EFFECTS OF TRUNCAL VAGOTOMY AND PARTIAL GASTRECTOMY ON THE PHARMACOKINETICS OF PROPRANOLOL ENANTIOMERS IN DOGS

The effect of partial gastrectomy on the pharmacokinetic parameters of (+)‐ and (–)‐propranolol were investigated in six dogs. (±)‐Propranolol (3 mg/kg body weight) was administered orally before and after surgery and the plasma concentrations of (+)‐ and (–)‐propranolol were determined using an indirect enantioseparation technique. There were significant differences (p ⩽ 0.05, paired t‐test) in the area under the concentration–time curves (AUCs) and the maximum plasma concentration (Cmax) between (+)‐ and (–)‐propranolol. The ratio AUC(+):AUC(–) was 1.73 ± 0.28. These differences between the enantiomers remained unchanged after surgery. Other pharmacokinetic parameters showed no stereoselectivity. After partial gastrectomy, there was a slight, but nonsignificant decrease in time to reach maximum plasma concentration (tmax) and in the absorption half‐life for both enantiomers. The maximum plasma concentration increased slightly. The elimination half‐life and the mean residence time remained unchanged before and after surgery. Therefore, it is unlikely that there are any clinically relevant changes in the pharmacokinetics of (+)‐ and (–)‐propranolol after partial gastrectomy. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company