11C-coenzyme Q10: a new myocardial imaging tracer for positron emission tomography.

Coenzyme Q10 (CoQ10) is a co-factor of the mitochondrial electron-transfer system. 11C-Labeled CoQ10 was synthesized and its biodistribution in rats was examined comparing two kinds of preparation methods using different emulsifiers as a basic study for application of positron emission tomography. 11C-CoQ10 emulsified in saline with polyoxyethylene hydrogenated castor oil was present in the highest concentration in the blood at 30 min. On the other hand, the 11C-CoQ10 emulsified with phospholipids was rapidly cleared from the blood. The liver and spleen uptakes were high probably due to endocytosis, reflecting the characteristics of liposomes. The myocardial uptake was also high just after administration, and the heart-to-blood concentration ratio was over 10 after 5 min. These results suggest that 11C-CoQ10 prepared with liposomes may be a myocardial imaging tracer.