Pharmacokinetics of epirubicin emulsion and solution in rabbits after intrahepato-arterial and intravenous injection.

The study reports pharmacokinetic findings on the disposition of a formulated emulsion of epirubicin in rabbits as compared to plain epirubicin solution after intrahepato-arterial and intravenous administration. The dose of epirubicin used was 1 mg/kg body weight. Blood samples were collected at several time points up to 6 h after administration. Serum concentrations of epirubicin were measured by liquid chromatography with fluorometric detection. The area under serum concentration-time curve (AUC infinity 0) is smallest after intrahepato injection of epirubicin emulsion. This, together with the highest apparent volume of distribution (Vss) suggest a possible targetting effect. Although the mean residence times are similar, intrahepato injection of emulsion apparently has the largest clearance. Difference in bioavailability in the general circulation between the 2 routes of administration also suggests a certain degree of liver first-pass metabolism of the drug. In view of these findings, further investigation and assessment are worthwhile for future application in human subjects.