Pharmacokinetic evaluation of D-ribose after oral and intravenous administration to healthy rabbits

INTRODUCTION: This study explored D-ribose pharmacokinetics after intravenous (IV) and oral administration to healthy rabbits. MATERIALS AND METHODS: D-ribose was administered once as 420 mg/kg (N=4) or 840 mg/kg (N=6) dose intravenously, or as an oral dose of 420 mg/kg (N=3) or 840 mg/kg (N=3). Serum was obtained at various time points, up to 210 minutes after administration. Urine was also collected after IV administration. Pharmacokinetic parameters were determined from drug concentration–time data using Kinetica software. RESULTS: The findings showed that D-ribose follows a dose-dependent kinetic profile. With doubling the IV dose, AUC(total) was significantly increased by threefold, while the clearance was decreased by 44%. The half-life was 1.7-fold longer at the higher dose. Similar nonsignificant trends were also observed at oral administration. D-ribose was rapidly absorbed (T(max)=36–44 minutes) and rapidly disappeared from plasma (within <140 minutes). Additionally, D-ribose was partially (18–37.5%) recovered from urine. CONCLUSION: Collectively, D-ribose showed a dose-dependent kinetic profile, where parameters change according to dosing levels. D-ribose clearance seems to follow first-order kinetics at low dose. Thereafter, elimination systems are saturated, and elimination continues in a fast manner. Urine recovery was partial, which could be attributed to the several metabolic pathways that pentose can undergo.