Plasma bevantolol concentration and heart rate in rabbits

Bevantolol (Bev, 5, 10 mg.kg-1) was injected i.v. to rabbits. A measure the lag time of heart rate (HR) response behind the changes in plasma Bev concentration (K(eo)), and the sensitivity of the site of action of Bev (EC50) were determined. The K(eo) were 0.03 +/- 0.02 and 0.029 +/- 0.009 min-1 and the EC50 were 0.2 +/- 0.1 and 0.27 +/- 0.14 microgram.ml-1 respectively for the 2 dosages. The peak changes in HR lagged behind the changes in plasma Bev concentration. There were no significant changes in both pharmacokinetic and pharmacodynamic parameters between the dosages.