The quality control assessment of commercially available coenzyme Q ₁₀-containing dietary and health supplements in Japan

Coenzyme Q₁₀ (CoQ₁₀) has been widely commercially available in Japan as a dietary and health supplement since 2001 and is used for the prevention of lifestyle-related diseases induced by free radicals and aging. We evaluated CoQ₁₀ supplements to ensure that these supplements can be used effectively and safely. Commercially available products were selected and assessed by the quality control tests specified in the Japanese Pharmacopoeia XV. When the disintegration time of CoQ₁₀ supplements was measured, a few tested supplements did not completely disintegrate even after incubation in water for an hour at 37°C. In the content test, many samples were well controlled. However, a few supplements showed low recovery rates of CoQ₁₀ as compared to manufacturer's indicated contents. Among soft capsule and liquid supplements, the reduced form of CoQ₁₀ (H₂CoQ₁₀), as well as the oxidized form, was detected by HPLC with electrochemical detector. The results for experimental formulated CoQ₁₀ supplements demonstrated that H ₂CoQ₁₀ was produced by the interaction of CoQ₁₀ with vitamins E and/or C. From these results, we concluded that quality varied considerably among the many supplement brands containing CoQ₁₀. Additionally, we also demonstrated that H₂CoQ₁₀ can be detected in some foods as well as in CoQ₁₀ supplements.