Pharmacokinetic Profiles of Coenzyme Q 10: Absorption of Three Different Oral Formulations in Rats
Pharmacokinetics and absorption profiles of coenzymeQ 10 (CoQ 10) from three different oral formulations were evaluated in rats. For the intravenous concentration-time data, a two-compartment open model fitted well. There were no significant changes in the values of the elimination rate constant at the terminal phase, and the half-life of CoQ 10 was estimated to be 7 to 8 hr. The values of intravenous area under the plasma concentration-time curve up to infinity (AUC ∞) increased with a rise in CoQ 10 dose (0.025 to 2.5 mg/kg); however, the AUC ∞ showed a nonlinear relationship with the administered dose. The total body clearance (CL tot) increased with a rise in the intravenous dose of CoQ 10 . The value of CL tot increased in proportion to the intravenous dose. Three different formulations of CoQ 10 [olive oil solution (control), sub-nanosize particles and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-emulsion] were tested in rats. An appropriate compartment model wasn't adapted to the concentration-time data from orally administered CoQ 10 formulations because plasma concentrations of CoQ 10 from 10 to 24 hr after administration were markedly increased for all formulations tested. The TPGS-emulsion showed a significantly higher AUC 0−24 value and absorption rate (Fa) than the other formulations (AUC 0−24 , 18876 ± 6225 ng · h/ml; Fa, 0.15%). There was no difference in the values of AUC 0−24 and Fa between the control and subnano-particle formu-lations. After intraloop administration of CoQ 10 in the olive oil formulation, there were no significant differences in the plasma concentration of CoQ 10 , and the residual amounts of CoQ 10 in the different parts of the intestinal loop (upper jejunum, lower jejunum, ileum) at the end of experiment were almost the same. These observations indicate that the pharmacokinetics of CoQ 10 are nonlinear, and suggest the existence of a deep compartment for CoQ 10 accumulation in the intestine. Absorption of CoQ 10 from the intestine was very poor; however, a higher plasma concentration of CoQ 10 was achieved by an emulsion formulation using TPGS.