As previously stated, CoQ
10 is practically insoluble in aqueous solutions, therefore, its oral or intestinal absorption is slow and extremely inefficient. However, its bioavailability can be substantially modified by using an adequate formulation for its administration. Since CoQ
10 is fat-soluble
[21], its absorption is enhanced when taken with a meal having a high oil/fat content. In line with this, oil-based formulations, such as emulsions where CoQ
10 is dissolved in an oil-dispersed phase, have proven to be successful for CoQ
10 delivery. The research in the field indicates that solubilized CoQ
10 formulations present a much higher bioavailability than non-solubilized powder-based CoQ
10 products
[22] meaning that a higher CoQ
10 plasma concentration could be achieved using lower doses of solubilized CoQ
10 formulations than those used with non-solubilized ones. Another factor supporting the use of solubilized formulations rather than traditional ones is the fact that mitochondrial and neurodegenerative disorders’ patients commonly struggle to swallow
[23][24]. Therefore, it is hard for them to deal with traditionally big CoQ
10 tablets or powder-filled capsules. In light of this evidence, the research is now focused on developing formulations with CoQ
10 solubilized either in liquid or jelly matrixes. Among the studies carried out in this direction, it is worth to point out the development of ethyl cellulose (EC)-oleogels for high-dose CoQ
10 oral administration (1 g of CoQ
10 per 5 g oleogel-disk)
[25]. Medium-chain triglyceride (MCT) oil was used to dissolve CoQ
10, since it is known to be the only fat that people with the inability to absorb or digest conventional fats tolerate
[26]. Moreover, two surfactants were evaluated to modulate the mechanical properties of the gels. SMS proved to be more convenient than lecithin, since it allowed a higher stability to oxidize the MCT oil and a better enhancement of CoQ
10 stability while lowering the syneresis in the final oleogels. Moreover, SMS-containing oleogels showed higher thermal stability than lecithin-containing ones.
The novelty of the aforementioned study lies in the fact that the SMS-containing oleogels allowed loading exceptionally high doses of soluble CoQ10 in soft gel structures that reduce the swallowing discomfort for patients. Additionally, the number of dosage units per day could be reduced since each of these oleogels provides a high dose of CoQ10. According to the authors, the CoQ10 dissolved in MCT was stable for 12 months when immobilized into the oleogels. Thereafter, neither storage nor distribution is a problem for the future translation of this formulation to the clinical practice.