Preclinical pharmacokinetics of beta-L-dioxolane-cytidine, a novel anticancer agent, in rats.

Abstract

beta-L-Dioxolane-cytidine (OddC), a novel L-nucleoside analog with potent cytotoxicity in vitro, appears to be a promising candidate for anticancer therapy. In this study, a high performance liquid chromatography (HPLC) analytical method was developed and the preclinical pharmacokinetics of OddC were characterized in rats. Adult male Sprague Dawley rats were given 10, 25, or 50 mg/kg of OddC both intravenously and orally with a 6-day washout period between doses. Each rat received one dosage level of OddC and the route of administration was assessed by a randomized crossover design. Plasma and urine concentrations were determined by HPLC. Pharmacokinetic parameters were generated by area-moment analysis. Following intravenous administration, the plasma concentrations of OddC declined rapidly in a biexponential manner with a terminal phase half-life of 1.65 +/- 1.12 h (mean +/- SD). Mean total, renal, and nonrenal clearances were 1.38 +/- 0.62, 0.30 +/- 0.14, and 1.08 +/- 0.59 1/h per kg. Approximately 22% of the administered dose was excreted unchanged in the urine. Thus, nonrenal clearance was the predominant route of elimination of OddC. The steady-state volume of distribution averaged 1.42 +/- 0.66 1/kg, indicating intracellular distribution of OddC. The nucleoside analog was slowly absorbed after oral administration and bioavailability varied greatly between individual rats, averaging 41 +/- 27% when calculated from urinary excretion data and 37 +/- 25% when calculated from plasma OddC concentration data. The pharmacokinetics of OddC in rats were linear over the dose range studied.