Preparation, Characterization and Evaluation of Coenzyme Q10 Binary Solid Dispersions for Enhanced Solubility and Dissolution

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.

Tablet characteristics and pharmacokinetics of orally disintegrating tablets containing coenzyme Q10 granules prepared by different methods

This study aimed to elucidate the characteristics and pharmacokinetics of orally disintegrating tablets (ODTs) containing coenzyme Q10 (CoQ10) granules prepared by spray drying, hot-melting, and wet granulation. The hardness and disintegration times of CoQ10-ODTs containing 5 % crospovidone were 61.6-81.8 N and < 30 s, respectively; these values indicate that the as-prepared ODTs were adequate for clinical use. The hardness and disintegration times of all ODTs did not change significantly after a 28-day storage period at 30 °C/10 % relative humidity (RH), but storage under high temperature and humidity affected their characteristics. The dissolution and pharmacokinetics of CoQ10-ODTs showed that ODTs prepared using the spray-drying method had the highest dissolution and absorbability among the CoQ10-ODTs tested. These results provide useful information for the preparation of ODTs using CoQ10.

The Use of the Coenzyme Q10 as a Food Supplement in the Management of Fibromyalgia: A Critical Review

The coenzyme Q₁₀ is a naturally occurring benzoquinone derivative widely prescribed as a food supplement for different physical conditions and pathologies. This review aims to sum up the key structural and functional characteristics of Q₁₀, taking stock of its use in people affected by fibromyalgia. A thorough survey has been conducted, using Pubmed, Scifinder, and ClinicalTrials.gov as the reference research applications and registry database, respectively. Original articles, reviews, and editorials published within the last 15 years, as well as open clinical investigations in the field, if any, were analyzed to point out the lights and shadows of this kind of supplementation as they emerge from the literature.

Intrastriatal administration of coenzyme Q10 enhances neuroprotection in a Parkinson's disease rat model

Parkinson's disease is a neurodegenerative disorder, and no treatment has been yet established to prevent disease progression. Coenzyme Q10, an antioxidant, has been considered a promising neuroprotective agent; however, conventional oral administration provides limited efficacy due to its very low bioavailability. In this study, we hypothesised that continuous, intrastriatal administration of a low dose of Coenzyme Q10 could effectively prevent dopaminergic neuron degeneration. To this end, a Parkinson's disease rat model induced by 6-hydroxydopamine was established, and the treatment was applied a week before the full establishment of this disease model. Behavioural tests showed a dramatically decreased number of asymmetric rotations in the intrastriatal Coenzyme Q10 group compared with the no treatment group. Rats with intrastriatal Coenzyme Q10 exposure also exhibited a larger number of dopaminergic neurons, higher expression of neurogenetic and angiogenetic factors, and less inflammation, and the effects were more prominent than those of orally administered Coenzyme Q10, although the dose of intrastriatal Coenzyme Q10 was 17,000-times lower than that of orally-administered Coenzyme Q10. Therefore, continuous, intrastriatal delivery of Coenzyme Q10, especially when combined with implantable devices for convection-enhanced delivery or deep brain stimulation, can be an effective strategy to prevent neurodegeneration in Parkinson's disease.

Green Formulation of Triglyceride/Phospholipid-Based Nanocarriers as a Novel Vehicle for Oral Coenzyme Q10 Delivery

This study was aimed to develop a novel nanocarrier for coenzyme Q10 (CoQ10) by a green process that prevented the use of surfactants and organic solvents. Triglyceride/phospholipid-based nanocarriers were developed through high-pressure homogenization (an industrial feasible process), and a 2^5-1 fractional factorial design was adopted to assess the influences of formulation variables on the considered responses, including vesicle size, entrapment efficiency, loading capacity, and solubility of the vehicles in simulated gastrointestinal fluids. The optimized formulation was further in-depth characterized in terms of morphology, release behavior, biocompatibility (Caco-2 cell cytotoxicity and histological examination), thermal behavior, and Fourier transform infrared analysis. Optimal nanocarriers were found to have mean particle size of 75 nm, narrow particle distribution, and CoQ10 entrapment of 95%. The optimized formulation was stable upon incubation in simulated gastrointestinal fluids without considerable leakage of cargo, which was in agreement with their sustained release behavior. Microscopic observations also confirmed nanosized nature of the vesicles and revealed their spherical shape. Moreover, toxicity evaluations at the cellular and tissue levels revealed their nontoxic nature. In conclusion, triglyceride/phospholipid-based nanocarriers proved to be a green safe vehicle for delivery of CoQ10 with industrial-scale production capability and could provide a new horizon for delivery of hydrophobic nutraceuticals. PRACTICAL APPLICATION: Green nanostructure formulation approaches have recently gained tremendous attraction for their safe profile especially when it comes to supplements, which are generally recommended for daily use. However, their sufficient association with cargoes and industrial-scale production have remained considerable challenges. This study focuses on the development of lipid-based nanocarriers for CoQ10 by an industrial feasible process that prevents the use of any surfactants or organic solvents.

Preparation and Characterization of Mucoadhesive Nanoparticles for Enhancing Cellular Uptake of Coenzyme Q10

The mucoadhesive nanoparticles (NPs) for oral delivery of coenzyme Q10 (CoQ10) were prepared using natural mucoadhesive polysaccharides, chitosan (CS), and dextran sulfate sodium salt (DS) in order to improve the solubility, cellular uptake, and thermo- and photostability of CoQ10. CoQ10-loaded NPs were prepared in the range of 340-450 nm with an entrapment efficiency of 60-98%. The mucoadhesiveness and cellular uptake of NPs were evaluated by measuring the amount of mucin adsorbed on NPs and CoQ10 absorbed in Caco-2 cells, respectively. CS/DS NPs had higher mucoadhesive strength than CS/sodium triphosphate pentabasic NPs (control group). Moreover, the solubility, cellular uptake, thermo- and photostability of CS/DS NPs were significantly improved compared with non-nanoencapsulated free CoQ10. Particularly, CS/DS NPs prepared with 0.5 mg/mL of CS and DS produced the highest mucoadhesiveness, solubility, cellular uptake, and cellular antioxidant activity. Thus, mucoadhesive CS/DS NPs may be an effective oral delivery platform for improving bioavailability of CoQ10.

Kolliphor® HS 15 Micelles for the Delivery of Coenzyme Q10: Preparation, Characterization, and Stability

To enhance the stability of coenzyme Q10 (CoQ10), Kolliphor® HS 15 (HS15) was employed as a carrier to build up a stable CoQ10-loaded micelle delivery system. The impact of micellar compositions, the preparation condition, and the preparation method on size characteristics, the solubilization efficiency, and micellar stability were investigated. The optimal preparation conditions were 1:6, 4, 0.2%, 118°C, and 25 min for CoQ10/HS15 mass ratio, pH value, the concentration of glucose, and the sterilization conditions. Upon these conditions, the particle size, polydispersity index (PDI), zeta potential, the entrapment efficiency, drug loading, and the critical micelle concentration (CMC) of CoQ10-loaded micelles were 19.76 nm, 0.112, -3.405 mV, 99.39%, 13.77%, and 5.623 × 10(-4) g/mL, respectively. Differential scanning calorimetry (DSC) analysis collectively corroborated that CoQ10 was entrapped into the micelles in amorphous form. The release pattern of drug was analyzed and proved to follow the first order. Additionally, the samples were exposed to the temperatures of 30°C for 6 months with more significant impact on their stabilities as compared to 4 and 25°C based on particle size and PDI. Under constant humidity with light protection long-term (25 ± 2°C, relative humidity (RH) 60 ± 10%, 18 months) conditions, there was no variation except minor changes of CoQ10 content of the samples. The shelf life of the micellar samples could be predicted as 24 months based on the stability results. Consequently, the CoQ10-loaded micelles showed excellent stabilities below 25°C as a potential drug candidate for further clinical applications.

Emulsion formulation optimization and characterization of spray-dried κ-carrageenan microparticles for the encapsulation of CoQ10

The present study is aimed to prepare κ-carrageenan microparticles for the encapsulation of model drug, coenzyme Q10 (CoQ10). A face-centered central composite design was employed to study the effects of three different formulation variables (κ-carrageenan, emulsifier, and oil). The powder yield was found inversely affected by the κ-carrageenan and oil concentration. The encapsulation efficiency was maximized in the region of the middle level κ-carrageenan concentration, the high level emulsifier concentration, and the low level oil concentration. The emulsifier concentration was the most influential variable on the particle size of powder. The optimal formulation was reported as 0.91% (w/v) κ-carrageenan concentration, 0.64% (w/v) emulsifier, and 1.0% (w/w) oil. Both differential scanning colorimeter and X-ray diffraction analyses proved that incorporation of CoQ10 into κ- carrageenan microcapsules resulted in amorphous powder with significantly (p<0.05) higher water solubility compared to pure CoQ10 and physical mixture in the crystalline form.

Preparation, in-vitro and in-vivo characterisation of CoQ10 microparticles: electrospraying-enhanced bioavailability

Objectives

This study aimed to prepare Coenzyme Q10 (CoQ10) microparticles using electrospraying technology, and evaluate the in-vitro properties and in-vivo oral bioavailability.

Key findings

Electrospraying was successfully used to prepare CoQ10 to enhance its solubility and dissolution properties. In-vitro evaluation of the electrosprayed microparticles showed bioavailability-enhancing properties such as reduced crystallinity and particle size. The formulation was evaluated using dissolution study and in-vivo oral bioavailability using rat model. The dissolution study revealed enhanced dissolution properties of electrosprayed microparticles compared with physical mixture and raw material. The absorption profiles showed increasing mean plasma levels CoQ10 in the following order: raw material &lt; physical mixture &lt; electrosprayed microparticles.

Conclusion

Based on the findings in this study, electrospraying is a highly prospective technology to produce functional nano- and micro-structures as delivery vehicles for drugs with poor oral bioavailability due to rate-limiting solubility.

Effect of hydroxypropylcellulose and Tween 80 on physicochemical properties and bioavailability of ezetimibe-loaded solid dispersion

The purpose of this research was to evaluate the effect of the HPC (hydroxypropylcellulose) and Tween 80 on the physicochemical properties and oral bioavailability of ezetimibe-loaded solid dispersions. The binary solid dispersions were prepared with drug and various amounts of HPC. Likewise, ternary solid dispersions were prepared with different ratios of drug, HPC and Tween 80. Both types of solid dispersions were prepared using the solvent evaporation method. Their aqueous solubility, physicochemical properties, dissolution and oral bioavailability were investigated in comparison with the drug powder. All the solid dispersions significantly improved the drug solubility and dissolution. As the amount of HPC increased in the binary solid dispersions to 10-fold, the drug solubility and dissolution were increased accordingly. However, further increase in HPC did not result in significant differences among them. Similarly, up to 0.1-fold, Tween 80 increased the drug solubility in the ternary solid dispersions followed by no significant change. However, Tween 80 hardly affected the drug dissolution. The physicochemical analysis proved that the drug in binary and ternary solid dispersion was existed in the amorphous form. The particle-size measurements of these formulations were also not significantly different from each other, which showed that Tween 80 had no impact on physicochemical properties. The ezetimibe-loaded binary and ternary solid dispersions gave 1.6- and 1.8-fold increased oral bioavailability in rats, respectively, as compared to the drug powder; however, these values were not significantly different from each other. Thus, HPC greatly affected the solubility, dissolution and oral bioavailability of drug, but Tween 80 hardly did. Furthermore, this ezetimibe-loaded binary solid dispersion prepared only with HPC would be suggested as a potential formulation for oral administration of ezetimibe.

Strategies for oral delivery and mitochondrial targeting of CoQ10

Coenzyme Q10 (CoQ10), also known as ubiquinone or ubidecarenone, is a powerful, endogenously produced, intracellularly existing lipophilic antioxidant. It combats reactive oxygen species (ROS) known to be responsible for a variety of human pathological conditions. Its target site is the inner mitochondrial membrane (IMM) of each cell. In case of deficiency and/or aging, CoQ10 oral supplementation is warranted. However, CoQ10 has low oral bioavailability due to its lipophilic nature, large molecular weight, regional differences in its gastrointestinal permeability and involvement of multitransporters. Intracellular delivery and mitochondrial target ability issues pose additional hurdles. To maximize CoQ10 delivery to its biopharmaceutical target, numerous approaches have been undertaken. The review summaries the current research on CoQ10 bioavailability and highlights the headways to obtain a satisfactory intracellular and targeted mitochondrial delivery. Unresolved questions and research gaps were identified to bring this promising natural product to the forefront of therapeutic agents for treatment of different pathologies.

New self-nanoemulsifying drug delivery system (SNEDDS) with amphiphilic diblock copolymer methoxy poly (ethylene glycol)-block-poly (ε-caprolactone)

The objective of the study is to prepare a new self-nanoemulsifying drug delivery system (SNEDDS) with amphiphilic diblock copolymers methoxy poly (ethylene glycol)-block-poly (ε-caprolactone) (MPEG-b-PCL) and to investigate the effect of MPEG-b-PCL on the characteristics of SNEDDS. MPEG-b-PCL was synthesized and characterized by (1)H-NMR, IR and GPC. Various ratios of MPEG-b-PCL copolymers and Tween 80 were used as emulsifier to prepare the new SNEDDS. SNEDDS with high oil and low surfactant content forms a semi-solid gel at room temperature, which could be effectively sealed in soft or hard capsules. The mean droplet size of SNEDDS-generated nanoemulsions significantly decreased after the addition of diblock polymer and increased with increase of PCL chain in MPEG-b-PCL. The drug Coenzyme Q10 (CoQ10) was chosen as the model compound in this study due to its insolubility in water. CoQ10 from SNEDDS was rapidly dissolved regardless of the fluid condition.

Novel solid self-emulsifying drug delivery system of coenzyme Q₁₀ with improved photochemical and pharmacokinetic behaviors

The present study was undertaken to develop a solid self-emulsifying drug delivery system of coenzyme Q(10) (CoQ(10)/s-SEDDS) with high photostability and oral bioavailability. The CoQ(10)/s-SEDDS was prepared by spray-drying an emulsion preconcentrate containing CoQ(10), medium-chain triglyceride, sucrose ester of fatty acid, and hydroxypropyl cellulose, and its physicochemical, photochemical, and pharmacokinetic properties were evaluated. The CoQ(10)/s-SEDDS powder with a diameter of ca. 15 μm was obtained by spray-drying, in which the CoQ(10) was mostly amorphized. The CoQ(10)/s-SEDDS exhibited immediate self-emulsification when introduced to aqueous media under gentle agitation, forming uniform fine droplets with a mean diameter of ca. 280 nm. There was marked generation of reactive oxygen species, in particular superoxide, from CoQ(10) exposed to simulated sunlight (250W/m(2)), suggesting potent photoreactivity. Nano-emulsified solution of CoQ(10) under light exposure underwent photodegradation with 22-fold higher degradation kinetics than crystalline CoQ(10), although the CoQ(10)/s-SEDDS was less photoreactive. After the oral administration of CoQ(10)/s-SEDDS (100 mg-CoQ(10)/kg) in rats, enhanced exposure of CoQ(10) was observed with increases in both C(max) and AUC of ca. 5-fold in comparison with those of orally administered crystalline CoQ(10). From the improved physicochemical and pharmacokinetic data, the s-SEDDS approach upon spray-drying might be a suitable dosage option for enhancing nutraceutical and pharmaceutical values of CoQ(10).

In vitro-in vivo study of CoQ10-loaded lipid nanoparticles in comparison with nanocrystals

The present work described the effect of CoQ10 dissolution characteristics in nanocrystals and lipid nanoparticles (LNs) on its oral absorption in rats. Nanocrystals and LNs were prepared by melt-high pressure homogenization and sucrose monolaurate was used as a stabilizer in all formulations. Witepsol(®)W35 and medium-chain triglycerides (MCT) were selected as lipid additives to form LN(CoQ10+W35) and LN(CoQ10+MCT), respectively. From the results obtained, the particle size of CoQ10 nanocrystals was 285 nm, while it was reduced to 150 nm by mixture with an equal amount of lipid additives due to their lower melting points. In vitro dissolution results indicated that the drug release from two LNs was delayed compared with that from nanocrystals, and LN(CoQ10+W35) exhibited the highest drug release over 4h. Finally, in vivo evaluation demonstrated that the oral absorption of CoQ10 was markedly increased by using nanocrystals and LNs compared with a coarse suspension. A good relationship was found between the in vitro dissolution and in vivo evaluation. The enhanced oral absorption of CoQ10 by nanocrystals and LNs was due to improved dissolution. In conclusion, Witepsol(®)W35 was shown to be a better lipid additive for the preparation of LNs to increase the oral absorption of CoQ10.

Solubilization of hydrophobic guest molecules in the monoolein discontinuous QL cubic mesophase and its soft nanoparticles

Hydrophobic bioactive guest molecules were solubilized in the discontinuous cubic mesophase (QL) of monoolein. Their effects on the mesophase structure and thermal behavior, and on the formation of soft nanoparticles upon dispersion of the bulk mesophase were studied. Four additives were analyzed. They were classified into two types based on their presumed location within the lipid bilayer and their influence on the phase behavior and structure. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), polarized light microscopy, cryogenic-transmission electron microscopy (cryo-TEM), and dynamic light scattering (DLS) were used for the analysis. We found that carbamazepine and cholesterol (type I molecules) likely localize in the hydrophobic domains, but close to the hydrophobic-hydrophilic region. They induce strong perturbation to the mesophase packing by influencing both the order of the lipid acyl chains and interactions between lipid headgroups. This results in significant reduction of the phase transition enthalpy, and phase separation into lamellar and cubic mesophases above the maximum loading capacity. The inclusion of type I molecules in the mesophase also prevents the formation of soft nanoparticles with long-range internal order upon dispersion. In their presence, only vesicles or sponge-like nanoparticles form. Phytosterols and coenzyme Q10 (type II molecules) present only moderate effects. These molecules reside in the hydrophobic domains, where they cannot alter the lipid curvature or transform the QL mesophase into another phase. Therefore, above maximum loading, excess solubilizate precipitates in crystal forms. Moreover, when type II-loaded QL is dispersed, nanoparticles with long-range order and cubic symmetry (i.e., cubosomes) do form. A model for the growth of the ordered nanoparticles was developed from a series of intermediate structures identified by cryo-TEM. It proposes the development of the internal structure by fusion events between bilayer segments.