Development of highly water-dispersible complexes between coenzyme Q10 and protein hydrolysates

Bioavailability enhancement of coenzyme Q10: An update of novel approaches

Coenzyme Q10 (CoQ10) is an essential, lipid-soluble vitamin involved in electron transport in the oxidoreductive reactions of the mitochondrial respiratory chain. Structurally, the quinone ring is connected to an isoprenoid moiety, which has a high molecular weight. Over the years, coenzyme Q10 has become relevant in the treatment of several diseases, like neurodegenerative disorders, coronary diseases, diabetes, hypercholesterolemia, cancer, and others. According to studies, CoQ10 supplementation might be beneficial in the treatment of CoQ10 deficiencies and disorders associated with oxidative stress. However, the water-insoluble nature of CoQ10 is a major hindrance to successful supplementation. So far, many advancements in CoQ10 bioavailability enhancement have been developed using novel drug carriers such as solid dispersion, liposomes, micelles, nanoparticles, nanoemulsions, self-emulsifying drug systems, or various innovative approaches (CoQ10 complexation with proteins). This article aims to provide an update on methods to improve CoQ10 solubility and bioavailability.

Investigation of the Potential of Selected Food-Derived Antioxidants to Bind and Stabilise the Bioactive Blue Protein C-Phycocyanin from Cyanobacteria Spirulina

Blue C-phycocyanin (C-PC), the major Spirulina protein with innumerable health-promoting benefits, is an attractive colourant and food supplement. A crucial obstacle to its more extensive use is its relatively low stability. This study aimed to screen various food-derived ligands for their ability to bind and stabilise C-PC, utilising spectroscopic techniques and molecular docking. Among twelve examined ligands, the protein fluorescence quenching revealed that only quercetin, coenzyme Q10 and resveratrol had a moderate affinity to C-PC (Ka of 2.2 to 3.7 × 105 M-1). Docking revealed these three ligands bind more strongly to the C-PC hexamer than the trimer, with the binding sites located at the interface of two (αβ)3 trimers. UV/VIS absorption spectroscopy demonstrated the changes in the C-PC absorption spectra in a complex with quercetin and resveratrol compared to the spectra of free protein and ligands. Selected ligands did not affect the secondary structure content, but they induced changes in the tertiary protein structure in the CD study. A fluorescence-based thermal stability assay demonstrated quercetin and coenzyme Q10 increased the C-PC melting point by nearly 5 °C. Our study identified food-derived ligands that interact with C-PC and improve its thermal stability, indicating their potential as stabilising agents for C-PC in the food industry.

Coenzyme Q10 Metabolism: A Review of Unresolved Issues

The variable success in the outcome of randomised controlled trials supplementing coenzyme Q10 (CoQ10) may in turn be associated with a number of currently unresolved issues relating to CoQ10 metabolism. In this article, we have reviewed what is currently known about these factors and where gaps in knowledge exist that need to be further elucidated. Issues addressed include (i) whether the bioavailability of CoQ10 could be improved; (ii) whether CoQ10 could be administered intravenously; (iii) whether CoQ10 could be administered via alternative routes; (iv) whether CoQ10 can cross the blood-brain barrier; (v) how CoQ10 is transported into and within target cells; (vi) why some clinical trials supplementing CoQ10 may have been unsuccessful; and (vii) which is the most appropriate tissue for the clinical assessment of CoQ10 status.

Enhanced water dispersibility and Caco-2 cell monolayer permeability of quercetin by complexation with casein hydrolysate

Although quercetin (Que) has many beneficial therapeutic effects on the human body, its oral bioavailability is poor because of its low water solubility. Herein, we describe the preparation of casein hydrolysate (Pep_cas ) and its use as a dispersant to enhance the water dispersibility of Que resulting in an improvement of its bioavailability. By complexation with Pep_cas , the apparent solubility of Que in the complex (Que@Pep_cas ) was significantly increased under acidic and neutral conditions. Que@Pep_cas was pre-digested in vitro using a simulated digestive juice, and a Caco-2 cell monolayer permeation assay was performed to evaluate the oral bioavailability of Que. The cumulative amount of Que that permeated the monolayer using Que@Pep_cas after 8, 16, and 24 h was increased compared with a blank sample (Que@Blank), and the apparent permeation coefficient P_app of Que@Pep_cas was approximately 2.6-fold better than that of Que@Blank. PRACTICAL APPLICATION: Pep_cas can be used as a high absorption supplement and food additive, and our Pep_cas complexation technique should be widely applicable to not only Que but also to other poorly water-soluble substances.

Dominant factors that determine the dissolution state of complexes between poorly water-soluble ingredients and casein hydrolysate

Casein hydrolysate (Pep) is a dispersant for poorly water-soluble drugs and nutraceutical ingredients. However, two types of complexes may be between Pep and poorly water-soluble molecules: those that are (1) dispersed as hydrocolloids in aqueous media with a particle size of 100-500 nm; and (2) not hydrocolloids, as indicated by permeability of the complex through an ultrafiltration (UF) membrane and the fact that the particle size is ambiguous by dynamic light scattering. This study was conducted to clarify the factors that determine the dissolution state of the complexes between poorly water-soluble ingredients and casein hydrolysate. We classified the dissolution state of the complexes between poorly water-soluble ingredients and Pep by the permeability using a UF membrane. Complexes containing larger and more-hydrophobic molecules are hydrocolloids and do not permeate the UF membrane, whereas complexes containing comparatively smaller and less-hydrophobic molecules do permeate the UF membrane. A complex containing indomethacin, which has borderline solubility properties, does not permeate the UF membrane at pH values in which the indomethacin carboxylic acid group is protonated, but it is permeable at pH values in which its carboxylic acid group is deprotonated. Furthermore, we determined the stoichiometry and association constant for the complex between a major peptide in Pep and poorly water-soluble resveratrol (Res) based on fluorescence quenching. We calculated the stoichiometry of Res and PepY to be 2:3 and the association constant to be 2.4 × 10⁷ M^-1.

Dendrimer-like glucan nanoparticulate system improves the solubility and cellular antioxidant activity of coenzyme Q10

Aqueous coenzyme Q10 (CoQ10) dispersions were prepared using sugary maize dendrimer-like glucan (SMDG) with solid-dispersion treatment. After measuring solubility, recovery rate and loading rate, the initial weight ratio of CoQ10:SMDG was optimized to be 1:27, with the solubility markedly increasing up 188.8-folds compared to pure CoQ10 solution. The structural characterizations of CoQ10-SMDG formulation showed crystal CoQ10 was entrapped in SMDG matrix for amorphous state, associated with the strong interactions with glucan chains. The antioxidant activity of CoQ10-SMDG was assessed via DPPH and FRAP assay. DPPH scavenging activity and FRAP value of it were as high as 95.1% and 0.87 mM, respectively. The cellular uptake of CoQ10 in CoQ10-SMDG group was significantly higher than that of natural CoQ10. CoQ10-SMDG also exhibited significant protective effects against cellular damage in H₂O₂-induced HaCaT cell model. The results indicated that dendrimer-like glucan is an excellent platform to encapsulate and improve biological activity of hydropholic compounds.

Bioavailability of Coenzyme Q10: An Overview of the Absorption Process and Subsequent Metabolism

A lack of understanding of the processes determining the absorption and subsequent metabolism of coenzyme Q₁₀ (CoQ₁₀) has resulted in some manufacturers’ making incorrect claims regarding the bioavailability of their CoQ₁₀ supplements, with potential consequences for the use of such products in clinical trials. The purpose of the present review article is, therefore, to describe the various stages of exogenous CoQ₁₀ metabolism, from its first ingestion, stomach transit, absorption from the small intestine into the lymphatic system, transport in blood, and access into cells. In particular, the importance of CoQ₁₀ crystal dispersion in the initial formulation is emphasised, the absence of which reduces bioavailability by 75%. In addition, evidence comparing the relative bioavailability and efficacy of ubiquinone and ubiquinol forms of CoQ₁₀ has been reviewed.

Microparticles, Microspheres, and Microcapsules for Advanced Drug Delivery

Microparticles, microspheres, and microcapsules are widely used constituents of multiparticulate drug delivery systems, offering both therapeutic and technological advantages. Microparticles are generally in the 1–1000 µm size range, serve as multiunit drug delivery systems with well-defined physiological and pharmacokinetic benefits in order to improve the effectiveness, tolerability, and patient compliance. This paper reviews their evolution, significance, and formulation factors (excipients and procedures), as well as their most important practical applications (inhaled insulin, liposomal preparations). The article presents the most important structures of microparticles (microspheres, microcapsules, coated pellets, etc.), interpreted with microscopic images too. The most significant production processes (spray drying, extrusion, coacervation, freeze-drying, microfluidics), the drug release mechanisms, and the commonly used excipients, the characterization, and the novel drug delivery systems (microbubbles, microsponges), as well as the preparations used in therapy are discussed in detail.