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.