Tissue distribution of propafenone in the rat after intravenous administration.

Tissue distribution of propafenone has been studied in the rat. Measurement of propafenone was made in several tissues: plasma, heart, kidney, lung, liver, muscle, fat and brain, after i.v. administration of 2 mg/kg of the drug. The plasma propafenone kinetics profile can be described by a two-compartmental model. The pharmacokinetic parameters, derived from plasma levels, showed a t1/2 beta of 55.4 min, the central Vd/kg of 2.4 ml/kg, the Cl of 62.8 ml/min.kg and the AUC0-oo of 31.6 micrograms.min/ml. The analysis of the propafenone tissue distribution showed the highest concentration of drug in the lung, followed by the heart and kidneys. A significant concentration was found in brain, muscle and adipose tissue, with concentration ratios (tissue/plasma) above 1. The half-life values obtained for individual organs and tissues are similar to those obtained in plasma, around 1 h. In the post-distributive phase, plasma and tissue concentrations decline in parallel.

Propafenone kinetics in the horse. Comparative analysis of compartmental and noncompartmental models.

The propafenone kinetics after intravenous (i.v.) administration have been studied in the horse by a comparative analysis of compartmental and noncompartmental models. The pharmacokinetic parameters showed a large distribution (Vdss = 1021 +/- 211 L) and a high clearance (CI = 7019 +/- 1746 mL/min) of the drug. The plasma concentrations were very low, under 1 microgram/mL, in most cases; after 30 min these concentrations can be considered as nonefficient for the treatment of arrhythmia. There were no significant differences between pharmacokinetic parameters found with the use of compartmental and noncompartmental models.