Pharmacokinetics and Tissue Distribution of Oxidized and Reduced Coenzyme Q10 Upon Intravenous Administration

Drugs containing coenzyme Q10 (CoQ10) in the oxidized (ubiquinone) or reduced forms (ubiquinol) are used to treat diseases associated with redox imbalance and are intended only for peroral administration. Parenteral solubilized forms of CoQ10 could fully reveal its therapeutic potential because of its low bioavailability. This study was aimed at comparing the pharmacokinetics and tissue distribution of CoQ10 upon intravenous administration of new dosage forms of ubiquinone and ubiquinol. Preparations (1% aqueous solutions with similar excipient compositions) were administered intravenously to rats (single dose, 30 mg/kg). Samples of blood, myocardium, brain, liver, and kidneys were taken for 8 d after administration using five rats for each time point. The CoQ10 content was determined by HPLC-EC. The AUC and Cl values were calculated. It was found that replenishment of the CoQ10 tissue content in individual organs was equally successful despite different total clearances of ubiquinol and ubiquinone, which implied they were equally effective upon intravenous administration.