Pharmacokinetic Study on Three Formulations of Coenzyme Q10 With Different Carriers

Benefits and importance of CoQ10 for the human health:

Coenzyme Q10 (CoQ10) is an endogenously produced lipid-soluble molecule of the human organism that is considered an essential component of the mitochondrial electron transport chain where it is the electron acceptor for complexes I and II. In this context, CoQ10 plays a key role in mitochondrial oxidative phosphorylation and ATP production and therefore it is essential for all energy-dependent processes in the body, enhancing the immune-system and acting as a free radical scavenger. In addition to its abundant presence in the mitochondrion, CoQ10 is found in other organelles such as endoplasmic reticulum, peroxisomes, lysosomes and vesicles. It is a membrane stabilizer, preserves myocardial sodium-potassium ATPase activity, and stabilizes myocardial calcium-dependent ion channels. Several factors such as ageing, poor eating habits, stress and infection, are known to affect the organism's ability to continue synthesizing and providing the adequate amounts of CoQ10. With age, the human organism begins to develop a CoQ10 deficiency due to its inability to synthesize it from food where it is present in beef, poultry, broccoli, soya oil and peanuts. In this context, several researchers have advised using CoQ10 supplements alone or in combination with other nutritional supplements to alleviate this deficiency and help maintain health of elderly people or treat some of the health problems or diseases. Due to these functions, CoQ10 finds its application in different commercial branches such as food, cosmetic, or pharmaceutical industries. The antioxidant activity of CoQ10 surpasses both in the amount and in efficiency other antioxidants. The protective effect is extended to lipids proteins and DNA mainly because of its close localization to the oxidative events and the effective regeneration by continuous reduction at all locations. CoQ10 in its reduced form as a hydroquinone (ubiquinol) is a potent lipophilic antioxidant that has a great importance as a free radical scavenger. CoQ10 protects the stability of the cell membranes, protects DNA from free radical induced oxidative damage, and is capable of recycling and regenerating other antioxidants, such as tocopherol and ascorbate. Other important functions of CoQ10 as e.g. cell signaling and gene expression have also been described.

Absorption and Transport of CoQ10:

Taking its lipophilic nature, the absorption of CoQ10 is enhanced in the presence of lipids with the main role attributed to the intestinal secretions from the pancreas and bile that are known to facilitate emulsification and micelle formation required for the fats absorption. Either during or following its absorption in the intestine, CoQ10 is reduced to ubiquinol, incorporated into chylomicrons and then transported via the lymphatics to the circulation where about 95% of CoQ10 in circulation exists in its reduced form as ubiquinol in human subjects. Plasma CoQ10 concentrations are highly dependent on plasma lipoproteins where CoQ10 redistributes possibly to protect lipoproteins from oxidation. Several factors have highlighted the poor absorption of orally administered CoQ10 such as its insolubility in water, limited solubility in lipids, and relatively large molecular weight. A preclinical study has reported that only about 2-3% of orally-administered CoQ10 was absorbed. Additionally, the absorption of CoQ10 and its bioavailability have been shown to be dependent on other factors such as the nature of the formulation of CoQ10 with solubilized formulations been reported to have an advanced effect on the bioavailability.

Tissue distribution of CoQ10 in humans and animals: