Dietary supplements are gaining wide popularity in Japan and are used by a large number of patients as self-medication. Though dietary supplements cannot be considered as drugs, patients expect pharmacological benefits from them since they usually have very little knowledge of their effects. Thus, pharmacists have the responsibility to expand their knowledge of dietary supplements so that they can give better advice to patients who are using them. However, only a limited amount of information on dietary supplements is available to pharmacists.
In the present study, we evaluated the content and solubility of coenzyme Q10 (ubidecarenone, CoQ10) in dietary supplements. CoQ10 is not only used as a dietary supplement, it is also prescribed as a drug by physicians. CoQ10 preparations were ground up and various techniques were used to extract the active ingredient, among them extraction using solvents, ultrasonication and heat. We found that the prescription drug preparations containing CoQ10, both original and generic products, had exactly the same content as stated on the label and had good solubility. Though dietary supplements containing CoQ10 also had the exact content stated on their labels, they showed poor solubility. Such poor solubility would give rise to major differences in elution and bioavailability between dietary supplements and prescription drugs containing CoQ10.
