Bioavailability assessment of oral coenzyme Q10 formulations in dogs

The purpose of this investigation was to compare the bioavailability of three coenzyme Q10 (CoQ10) formulations in dogs using an open, randomized, multiple-dose crossover design. The formulations included a powder-filled capsule (A, control) and two soft gelatin formulations (Q-Gel as the water-miscible form of CoQ10, B and Q-Nol as the water-miscible form of ubiquinol, the reduced form of CoQ10, C). Formulations were evaluated in pairs, allowing a washout period of 14 days prior to crossing over. Blood samples were collected from each animal prior to dosing to determine the endogenous plasma CoQ10 concentrations. Serial blood samples were collected for 72 hr and plasma CoQ10 concentrations were determined by high-performance liquid chromatography. Plasma concentration-time profiles were corrected for endogenous CoQ10 concentrations. Results showed that the relative bioavailabilities of formulations B and C were approximately 3.6 and 6.2-fold higher than that of control formulation A. The AUC(microgram.hr/mL) +/- SD, Cmax(microgram/mL) +/- SD, and Tmax(hr) +/- SD for formulations A, B, and C were 1.695 +/- 0.06, 6.097 +/- 0.08, and 10.510 +/- 0.10; 0.096 +/- 0.035, 0.169 +/- 0.038, and 0.402 +/- 0.102; and 4.2 +/- 1.48, 4.1 +/- 1.57, and 4.5 +/- 0.58, respectively. While no significant differences were observed between Tmax values of the three formulations, the AUC and Cmax values for formulations B and C were significantly higher than those of the control (p < 0.05). The present investigation demonstrates that soft gelatin capsules containing water-miscible CoQ10 formulations B (Q-Gel) and C (Q-Nol) are superior to powder-filled formulations with regard to their biopharmaceutical characteristics.