Comparative Pharmacokinetics of Free and Liposome-Encapsulated Catechin after Intravenous and Intraperitoneal Administration

Our previous studies demonstrated the efficacy of liposome-encapsulated catechin on the reduction of liver toxicity in rats with the injection of carbon-tetrachloride in vivo. In this investigation, pharmacokinetics of catechin after the injection of solution and liposomal catechin formulations developed in our laboratory were studied in rats. Two different formulations, one multilamellar vesicles (MLVs) intended for sustained release and other small unilamellar vesicles (SUVs) intended for targeted release were used. MLVs were injected by IP route while SUVs by IV route. Pharmacokinetic properties of liposome- encapsulated and free catechin were compared. Concentrations of the drug in plasma were determined by HPLC. PK analysis was performed using either WINNONLIN or KINETICA and both, compartmental and non-compartmental parameters were evaluated. Results indicated that, when catechin liposomal formulations were administered by IV and IP routes, mean residence time (MRT), half-life (t1/2) and the volume of distribution (Vd) were higher (P<0.05), and clearance (CL) was lower (P<0.05) than in the case of the free form. When the formulation was administered by I.P. route, the area under the curve (AUC) and the time to peak concentration (tmax) were significantly higher (P<0.05), and maximum concentration (Cmax) of catechin was lower than those of the free form. The results obtained in the present study showed that liposome encapsulated catechin provides the effective and prolonged plasma concentration after IV and IP administration