Improved high-performance liquid chromatographic method for the determination of coenzyme Q10 in plasma

Coenzyme Q10 and Autoimmune Disorders: An Overview

Some 90 autoimmune disorders have been described in medical literature, affecting most of the tissues within the body. Autoimmune disorders may be difficult to treat, and there is a need to develop novel therapeutic strategies for these disorders. Autoimmune disorders are characterised by mitochondrial dysfunction, oxidative stress, and inflammation; there is therefore a rationale for a role for coenzyme Q10 in the management of these disorders, on the basis of its key role in normal mitochondrial function, as an antioxidant, and as an anti-inflammatory agent. In this article, we have therefore reviewed the potential role of CoQ10, in terms of both deficiency and/or supplementation, in a range of autoimmune disorders.

Coenzyme Q10 and Endocrine Disorders: An Overview

Mitochondrial dysfunction and oxidative stress have been implicated in the pathogenesis of a number of endocrine disorders; this, in turn, suggests a potential role for the vitamin-like substance coenzyme Q10 (CoQ10) in the pathogenesis and treatment of these disorders, on the basis of its key roles in mitochondrial function, and as an antioxidant. In this article we have therefore reviewed the role of CoQ10 deficiency and supplementation in disorders of the thyroid, pancreas, gonads, pituitary and adrenals, with a particular focus on hyperthyroidism, type II diabetes, male infertility and polycystic ovary syndrome.

Technical Aspects of Coenzyme Q10 Analysis: Validation of a New HPLC-ED Method

The biochemical measurement of the CoQ status in different tissues can be performed using HPLC with electrochemical detection (ED). Because the production of the electrochemical cells used with the Coulochem series detectors was discontinued, we aimed to standardize a new HPLC-ED method with new equipment. We report all technical aspects, troubleshooting and its performance in different biological samples, including plasma, skeletal muscle homogenates, urine and cultured skin fibroblasts. Analytical variables (intra- and inter-assay precision, linearity, analytical measurement range, limit of quantification, limit of detection and accuracy) were validated in calibrators and plasma samples and displayed adequate results. The comparison of the results of a new ERNDIM external quality control (EQC) scheme for the plasma CoQ determination between HPLC-ED (Lab 1) and LC-MS/MS (Lab 2) methods shows that the results of the latter were slightly higher in most cases, although a good consistency was generally observed. In conclusion, the new method reported here showed a good analytical performance. The global quality of the EQC scheme results among different participants can be improved with the contribution of more laboratories.

Automated statistical experimental design approach for rapid separation of coenzyme Q10 and identification of its biotechnological process related impurities using UHPLC and UHPLC-APCI-MS

A novel ultra high performance liquid chromatography method development strategy was ameliorated by applying quality by design approach. The developed systematic approach was divided into five steps (i) Analytical Target Profile, (ii) Critical Quality Attributes, (iii) Risk Assessments of Critical parameters using design of experiments (screening and optimization phases), (iv) Generation of design space, and (v) Process Capability Analysis (Cp) for robustness study using Monte Carlo simulation. The complete quality-by-design-based method development was made automated and expedited by employing sub-2 μm particles column with an ultra high performance liquid chromatography system. Successful chromatographic separation of the Coenzyme Q10 from its biotechnological process related impurities was achieved on a Waters Acquity phenyl hexyl (100 mm × 2.1 mm, 1.7 μm) column with gradient elution of 10 mM ammonium acetate buffer (pH 4.0) and a mixture of acetonitrile/2-propanol (1:1) as the mobile phase. Through this study, fast and organized method development workflow was developed and robustness of the method was also demonstrated. The method was validated for specificity, linearity, accuracy, precision, and robustness in compliance to the International Conference on Harmonization, Q2 (R1) guidelines. The impurities were identified by atmospheric pressure chemical ionization-mass spectrometry technique. Further, the in silico toxicity of impurities was analyzed using TOPKAT and DEREK software.

Relative bioavailability of coenzyme Q10 formulation for paediatric individualized therapy

OBJECTIVES

Conduct a preliminary comparison of the bioavailability between two formulations: commercial grade coenzyme Q10 (CoQ10) powder (solid formulation) and a new oil-in-water liquid emulsion and their effect on other antioxidants.

METHODS

Six healthy individuals participated in a randomized, crossover, open, consecutive design, with a 2-week washout period. Pharmacokinetic parameters were assessed after a single and multiple intakes of 250 mg CoQ10 given daily for 1 week.

KEY FINDINGS

The differences in the pharmacokinetic parameters of maximum plasma concentration, area under the curve between 0-360 and 0-4 h, elimination half-life were statistically significant with a relative bioavailability of 489% increase over solid CoQ10 formulation. A multiple dose supplementation increased plasma CoQ10 levels in both formulations, liquid emulsion performing better (2.4- vs 3.9-fold for solid and liquid formulation, respectively) without modifications on other antioxidants. Furthermore, the plasma CoQ10 at 7th day was statistically different between formulations (P < 0.05).

CONCLUSIONS

The results obtained showed that liquid emulsion improves the bioavailability of CoQ10 respect to solid form which not only facilitates the individualized administration for the child but in turn could increase the therapeutic efficacy, which should be confirmed by further studies.

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.

New analytical strategies applied to the determination of Coenzyme Q10 in biological matrix

In the last few years the importance of Coenzyme Q10 (CoQ10) determination has gained clinical relevance. CoQ10 is a redox-active, lipophilic substance integrated in the mitochondrial respiratory chain which acts as an electron carrier for the production of cellular energy. In addition, it is recognized as a primary regenerating antioxidant playing an intrinsic role against oxidative damage. There are some reports of low CoQ10 levels in a number of disorders, such as cancer, muscular, neurodegenerative, cardiological, and reproductive diseases. Therefore, it is a priority to develop analytical methodologies for evaluating CoQ10 in matrices of greater importance for the correct diagnosis of diseases, simple enough to be used in routine clinical laboratories. In this chapter two recently developed techniques, capillary electrophoresis and microHPLC, for the analysis of CoQ10 in biological matrices, are studied.

Analytical problems with the determination of coenzyme Q10 in biological samples

The article discusses analytical problems related to the determination of coenzyme Q10 in biological samples. The assaying of coenzyme Q10 in complex samples, such as plasma, tissues, or food items requires meticulous sample preparation prior to final quantification. The process typically consists of the following steps: deproteinization, extraction, and ultimately reduction of extract volumes. At times drying under a gentle stream of neutral gas is applied. In the case of solid samples, a careful homogenization is also required. Each step of the sample preparation process can be a source of analytical errors that may lead to inaccurate results. The main aim of this work is to point to sources of analytical errors in the preparation process and their relation to physicochemical properties of coenzyme Q10. The article also discusses ways of avoiding and reducing the errors.

Measurement of oxidized and reduced coenzyme Q in biological fluids, cells, and tissues: an HPLC-EC method

Direct measure of coenzyme Q (CoQ) in biological specimens may provide important advantages. Precise and selective high-performance liquid chromatography (HPLC) methods with electrochemical (EC) detection have been developed for the measurement of reduced (ubiquinol) and oxidized (ubiquinone) CoQ in biological fluids, cells, and tissues. EC detection is preferred for measurement of CoQ because of its high sensitivity. Reduced and oxidized CoQ are first extracted from biological specimens using 1-propanol. After centrifugation, the 1-propanol supernatant is directly injected into HPLC and monitored at a dual-electrode. The EC reactions occur at the electrode surface. The first electrode transforms ubiquinone into ubiquinol, and the second electrode measures the current produced by the oxidation of the hydroquinone group of ubiquinol. The methods described provide rapid, precise, and simple procedures for determination of reduced and oxidized CoQ in biological fluids, cells, and tissues. The methods have been successfully adapted to meet regulatory requirements for clinical laboratories, and have been proven reliable for analysis of clinical and research samples for clinical trials and animal studies involving large numbers of specimens.

Kordiimonas lacus sp. nov., isolated from a ballast water tank, and emended description of the genus Kordiimonas

A Gram-negative, motile, rod-shaped bacterial strain, designated S3-22T, was isolated from a sediment sample collected from a ballast water tank of a commercial ship and subjected to a polyphasic taxonomic characterization. The isolate formed small, light-yellow, semi-translucent and circular colonies on solid complex media. The strain was oxidase- and catalase-positive and metabolized a large number of carbon sources. Chemotaxonomic analysis showed ubiquinone Q-10 as predominant respiratory quinone, phosphatidylglycerol and an unidentified glycolipid as major polar lipids and iso-C17 : 1 ω9c, iso-C15 : 0, C16 : 1 ω7c and/or iso-C15 : 0 2-OH, C16 : 0, iso-C17 : 0 and C18 : 1 ω7c as major fatty acids and the hydroxy fatty acids iso-C17 : 0 3-OH and C16 : 0 3-OH. The genomic DNA G+C content was 54.9 mol%. 16S rRNA gene sequence analysis revealed that the isolate has 96.1 % similarity to the type strain of Kordiimonas gwangyangensis, the sole described species within the order Kordiimonadales, and less than 91.0 % similarity to other recognized species. On the basis of phenotypic and genotypic data, strain S3-22T represents a novel species of the genus Kordiimonas, for which the name Kordiimonas lacus sp. nov. is proposed, with the type strain S3-22T (=CGMCC 1.9109T =JCM 16261T). An emended description of the genus Kordiimonas is also presented.

A randomized, double-blind, crossover study on the pharmacokinetics of a novel formulation of CoQ₁₀ with pyridoxal 5'-phosphate and phosphatidyl choline

The pharmacokinetics of a single 30-mg dose of a novel enteric-coated coenzyme Q10 (CoQ(10)) formulation with pyridoxal 5'-phosphate and phosphatidyl choline (CoQ(10)-P5P-PC) was investigated against two comparators CoQ(10) (NPN 02176955) and CoQ(10) (DIN 02231736) in 21 healthy volunteers, with screening CoQ(10) levels of 0.8 ± 0.2 mg/L. A randomized, double-blind, crossover study was designed with a washout period of 2 weeks between each formulation and blood sampled at 2, 4, 5, 6, 8, 12, 24, 48 and 72 hr postdose. Significantly, higher plasma concentrations were demonstrated for the CoQ(10) (NPN 02176955) formulation at 6 and 8 hr postdose (p = .010 and p = .042, respectively). There were no significant differences between formulations with respect to the area under the curve, AUC((0-72 hr)), or the maximum plasma concentration (C(max)). Total CoQ(10) (T(max)) reached maximum plasma concentrations at 6.4 ± 2.5 hr after supplementation with CoQ(10) (NPN 02176955), 8.0 ± 9.8 hr with CoQ(10)-P5P-PC, and 9.5 ± 9.3 hr with CoQ(10) (DIN 02231736). The estimated elimination half-life (t(1/2)) was 92.3 hr after a single oral dose of CoQ(10)-P5P-PC, 38.2 hr with CoQ(10) (NPN 02176955), and 80.7 hr with CoQ(10) (DIN 02231736). The results suggest that CoQ(10) is available for a longer time in subjects' administered with CoQ(10)-P5P-PC in comparison with the other two formulations studied. There were no significant differences in adverse events, by severity, causality, or organ system. The CoQ(10)-P5P-PC formulation was found to be superior in the t(1/2), and it may be suggested that fewer doses are required to maintain healthy circulatory CoQ(10) levels.

Coenzyme Q10: Absorption, tissue uptake, metabolism and pharmacokinetics

Available data on the absorption, metabolism and pharmacokinetics of coenzyme Q10 (CoQ10) are reviewed in this paper. CoQ10 has a fundamental role in cellular bioenergetics. CoQ10 is also an important antioxidant. Because of its hydrophobicity and large molecular weight, absorption of dietary CoQ10 is slow and limited. In the case of dietary supplements, solubilized CoQ10 formulations show enhanced bioavailability. The T(max) is around 6 h, with an elimination half-life of about 33 h. The reference intervals for plasma CoQ10 range from 0.40 to 1.91 micromol/l in healthy adults. With CoQ10 supplements there is reasonable correlation between increase in plasma CoQ10 and ingested dose up to a certain point. Animal data show that CoQ10 in large doses is taken up by all tissues including heart and brain mitochondria. This has implications for therapeutic applications in human diseases, and there is evidence for its beneficial effect in cardiovascular and neurodegenerative diseases. CoQ10 has an excellent safety record.

Decreased total serum coenzyme-Q10 concentrations: a longitudinal study in children with cystic fibrosis

OBJECTIVE

To assess total serum levels of coenzyme Q(10) (Co-Q(10)), an important antioxidant, in children with cystic fibrosis (CF) and to investigate an association between Co-Q(10) level and clinical outcome.

STUDY DESIGN

Co-Q(10) levels were measured annually in a prospective cohort study of 381 children with CF. A total of 1092 serum levels of total Co-Q(10) were obtained by high-performance liquid chromatography and ultraviolet light detection. Associations of Co-Q(10) with demographic variables and clinical outcomes were investigated.

RESULTS

Of the 381 initial total serum Co-Q(10) measurements, 188 were in the deficient range. Low Co-Q(10) was significantly more prevalent in patients with pancreatic insufficiency (PI) (55%) compared with patients with pancreatic sufficiency (PS) (3%); 22% of the patients with PI exhibited persistently low Co-Q(10) levels. Low Co-Q(10) levels were significantly associated with Pseudomonas aeruginosa colonization in patients with PI and CF under age 24 months, but not with subsequent lung function or hospitalization rates. Low Co-Q(10) levels were related to other markers of nutritional status, including total lipids, beta-carotene, and alpha-tocopherol.

CONCLUSIONS

Persistently low total serum Co-Q(10) levels are common in children with CF and PI. A prospective study is indicated to determine whether Co-Q(10) supplementation in CF is beneficial.

Determination of coenzyme Q10 and Q9 in vegetable oils

A new sensitive and selective method has been developed for the quantification of the total coenzyme Q9 (CoQ9) and coenzyme Q10 (CoQ10) concentration in vegetable oil samples. The coenzyme Q fraction is isolated by solid-phase extraction (SPE) on amino phase eluting with a mixture of heptane:ethyl ether. The organic solvent is evaporated under nitrogen, and the residue is dissolved in a mixture of acetonitrile:tetrahydrofuran and finally is analyzed by reverse-phase high-performance liquid chromatography with a mass detector. The sensitivity of the method is based on the high efficient formation of the radical anions [M (-.)] of CoQ9 and CoQ10 by negative atmospheric pressure ionization. Interferences are minimized by using mass detection of the [M (-.)] ions ( m/ z = 797.5 for CoQ9 and m/ z = 862.5 for CoQ10) in selective reaction monitoring mode ( m/ z = 797.5 --> m/ z = 779.5 and m/ z = 862.5 --> m/ z = 847.5) using a triple-quadrupole mass spectrometer. The method was successfully applied to sunflower, soybean, and rapeseed oils, with a limit of quantification of 0.025 mg/kg for both compounds.

Improved HPLC column-switching determination of Coenzyme Q and Vitamin E in plasma

A novel isocratic modified column-switching HPLC method for automated quantitative analysis of Vitamin E and Coenzyme Q, in the reduced and oxidized form, is described. Many column-switching HPLC methods are found in the literature, also for determining antioxidant substances, but we developed a different system of column-switching. An empty column, 5 cm long, was connected to the switching valve, before the sample loop and the extraction column. The sample loop was connected directly after the empty column. The inserted column, containing about 1.4 ml of the extraction eluent simulated a gradient elution, enhancing sensitivity and resolution. When switching the columns, the empty column is placed right before the extraction column and acts as a static mixer for the extraction phase and the incoming analytical phase. Samples were cleaned from interfering compounds by transfer onto a extraction-column, using a C-8 silica. Separation was performed onto an analytical column C18 3 m icrom, 150 mm x 4.6 mm at a flow rate of 1.0 ml/min with 20 mmol/l lithium perchlorate/perchloric acid, pH3.0 in Ethanol as analytical eluent. Detection was performed with a ESA Coulochem 5100 A model. The method was found to be suitable for automated analysis of Coenzyme Q, reduced and oxidized form, and Vitamin E in serum.

Analysis of CoQ10 in rat serum by ultra-performance liquid chromatography mass spectrometry after oral administration

A UPLC-MS method for determining Coenzyme Q(10) (CoQ(10)) levels in rat serum was developed. CoQ(10) was quantitatively extracted into 2-propanol using a fast extraction procedure. The separation of CoQ(10) was performed on a Waters Acquity UPLCtrade mark BEH C(18) column (1.7 microm, 1.0 mm x 50 mm) with the mobile phase containing acetonitrile, 2-propanol, and formic acid (90:10:0.1) over 5 min. The sensitivity of this method allows for the quantitation of 50 ng/mL CoQ(10) in serum (S/N=10). The linearity of this method was found to be from 50 to 20,000 ng/mL. The precision was less than 10% (intra- and inter-day), and the average extraction recovery was between 90 and 105%. This procedure provides a precise, sensitive and direct assay method for the determination of CoQ(10) in rat serum after oral administration. This method could be applied to further pharmacokinetic studies of CoQ(10).

Specific and rapid analysis of ubiquinones using Craven's reaction and HPLC with postcolumn derivatization

A new method for the analysis of ubiquinones in various samples was developed using an HPLC system with postcolumn derivatization. Craven's reaction, a specific color reaction for the analysis of ubiquinones, was used in the system. Because the reaction progressed in organic solvents that contained ubiquinones and ethylcyanoacetate under an alkaline condition, the selectivity for ubiquinone detection was higher than that for ubiquinone detection using the nonderivatized ultraviolet detection system at 275 nm, a system widely used for the analysis of ubiquinones. The new detection system can avoid the adverse effects of impurities. Furthermore, it can confirm specificity by stopping the color reaction under a neutral condition. The detection limit for ubiquinone-10 was 1 ng (1.2 pmol). A good linearity for the calibration curve was observed in the range of 11.7 pmol to 11.7 nmol. To investigate the possible application of this method, various samples, such as soybean capsules used as a dietary supplement and biological materials (rice as well as bovine plasma and liver samples), were applied to the system and their ubiquinone contents were quantified. This method is thought to be widely and conveniently applicable for determining the level of ubiquinones because of its high selectivity for ubiquinone detection.

Analysis of coenzyme Q in human blood and tissues

The major coenzyme Q species in humans is the decaprenyl quinoid derivative coenzyme Q10 (CoQ10), and its measurement is somewhat challenging owing to its hydrophobicity and tendency to be oxidized. There are three major methods which are suited for analysis of CoQ10: HPLC-coupled UV or electrochemical detection, and tandem mass spectrometry. The techniques are discussed, and results of these applications to determine CoQ10 concentrations in various human fluids and tissues are summarized.

Ubiquinol-10/lipids ratios in consecutive patients with different angiographic findings

OBJECTIVE

Information concerning un-supplemented plasma concentrations of ubiquinol-10 in coronary artery disease patients is still controversial. The aim of this study is to determine the levels of plasma ubiquinol-10 and ratios of ubiquinol-10 to plasma lipids in consecutive patients with different angiographic findings.

SUBJECTS AND METHODS

Thirty-six consecutive patients who underwent coronary angiography were split in two groups with different atherosclerotic changes. These patients were un-supplemented with antioxidants and were not treated by lipid-lowering medication. We have measured a plasma level of ubiquinol-10 using high-performance liquid chromatography with coulometric detection. Conventional plasma lipids, markers of oxidative stress and other widely accepted risk factors of atherosclerosis have been determined too.

RESULTS

Plasma ubiquinol-10 to low-density lipoprotein cholesterol (LDL-C) ratios in patients with different angiographic findings have been found as 180+/-69 and 132+/-43, respectively (p=0.020). The ubiquinol-10/LDL-C ratio was significantly lower in angiographically positive patients. There were also significant differences in ubiquinol-10 per total cholesterol (109+/-47 and 80+/-26, respectively; p=0.031), per triglycerides (426+/-191 and 237+/-86, respectively; p=0.002) and per the sum of triglycerides and total cholesterol (86+/-35 and 61+/-20, respectively; p=0.013).

CONCLUSIONS

There have not been found any significant differences between levels of widely accepted risk factors for genesis and progress of atherosclerotic changes in these two groups of patients. Only the level of triglycerides and the total cholesterol minus high-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio were significantly higher in patients with stenosis. This ratio correlated with the ubiquinol-10/LDL-C ratio, which was significantly lower in patients with stenosis. Our results indicate that the ratio of ubiquinol-10/LDL-C is likely to be a risk factor for atherogenesis.

FT-IR spectrophotometric analysis of coenzyme Q10 (CoQ10) and its pharmaceutical formulations

A Fourier transform infrared (FT-IR) spectrometric method was developed for the rapid, direct measurement of coenzyme Q10 (CoQ10) in different pharmaceutical products. Conventional KBr spectra were compared for the best determination of active substance in drug preparations. Lambert-Beer's law and two chemometric approaches, partial least squares (PLS) and principal component regression (PCR+) methods, were used in data processing.

Determination of coenzyme Q10 in human breast milk by high-performance liquid chromatography

An isocratic HPLC method was developed for the determination of coenzyme Q(10) (CoQ(10)) in human breast milk. After a single-step liquid-liquid extraction, the milk extract was injected directly into the HPLC system. The analytical method is based on pre-column inline treatment of CoQ(10). Chromatographic separation of CoQ(10) and coenzyme Q(9) (CoQ(9)) internal standard was achieved using a reversed-phase Microsorb-MV C(18) analytical column. CoQ(10) and CoQ(9) were monitored by an electrochemical detector (ECD). An excellent linearity (r = 0.999) was observed for CoQ(10) in the concentration range 0.06-2.5 micromol L(-1) in breast milk. The limit of quantitation (LOQ) was 60 nmol L(-1). Coefficients of variations (CVs) for intra-day and inter-day assay precisions were less than 5%. A total of 194 breast milk samples were analyzed for the CoQ(10) concentration; the mean value was 0.32 +/- 0.21 micromol L(-1).

Analytical method for ubiquinone-9 and ubiquinone-10 in rat tissues by liquid chromatography/turbo ion spray tandem mass spectrometry with 1-alkylamine as an additive to the mobile phase

We investigated the application of 1-alkylamines, as additives to the mobile phase, to a quantification method for ubiquinone-9 (CoQ9) and ubiquinone-10 (CoQ10) in rat thigh muscle and heart using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the optimization of the analytical method, we found that 1-alkylamines mixed with CoQ9 and CoQ10 in the turbo ion sprayed solution formed the 1-alkylammonium adduct molecules of these compounds during the ionization process and that the intensity of the adduct ions was considerably higher than that of the protonated molecules ([M+H]+) of these compounds. Furthermore, we investigated a variety of 1-alkylamines in the mobile phase for LC-MS/MS analysis to select the most appropriate 1-alkylamine for higher sensitivities of CoQ9 and CoQ10. After these examinations, we found that methylamine was the most suitable additive for the mobile phase, allowing a 12.5-fold gain in signal intensity in the full ion mass spectrum compared with that without methylamine. The internal standard (IS) used was ubiquinone-11 (CoQ11) for each analyte. The analytes and IS were extracted with methanol from the tissue homogenates at neutral pH and were injected into an LC-MS/MS with a turbo ion spray interface. The calibration curves for CoQ9 (5-500 microg/g in thigh muscle and 50-10,000 microg/g in heart) and CoQ10 (1-500 microg/g in thigh muscle and 10-10,000 microg/g in heart) showed good linearity. The method was precise; the relative standard deviations of the method for rat thigh muscle were not more than 13.5 and 9.0% for CoQ9 and CoQ10, respectively, and those for rat heart were not more than 6.7 and 5.4% for CoQ9 and CoQ10, respectively. The accuracies of the method for both rat thigh muscle and heart were good, with the deviations between the nominal concentration and calculated concentration of CoQ9 and CoQ10 typically being within 12.3 and 4.3%, respectively. This method provided reliable concentration levels for CoQ9 and CoQ10 in rat thigh muscle and heart.

Analysis of coenzyme Q(10) in human plasma by column-switching liquid chromatography

A new method of determining coenzyme Q10 in human plasma was developed based on column-switching high performance liquid chromatography (HPLC). CoQ10 was quantitatively extracted into 1-propanol with a fast one-step extraction procedure, after centrifugation, the supernatant was cleaned on an octadecyl-bonded silica column and then transferred to reversed-phase column by a column-switching valve. Determination of CoQ10 was performed on a reversed-phase analytical column with ultraviolet detection at 275 nm and the mobile phase containing 10% (v/v) isopropanol in methanol at a flow-rate of 1.5 ml/min. The sensitivity of this method allows the detection of 0.1 microg/ml CoQ10 in plasma (S/N=3). The linearity between the concentration and peak height is from 0.05 to 20 mg/l. The reproducibility (R.S.D.%) of the method is less than 2% (within day) and less than 3% (between day), the average recovery is 100.9 + 2.1%, it takes only 30 min to complete an analysis procedure, suitable for the determination of CoQ10 in human plasma especially for batch analysis in clinical laboratories. Finally, the method was applied to determine the plasma CoQ10 levels in healthy subjects, hyperthyroid and hypothyroid patients.

CoQ10 plasmatic levels in breast-fed infants compared to formula-fed infants

BACKGROUND

Coenzyme Q10 has been recognized as an important antioxidant factor besides its main role in bioenergetic metabolism. CoQ10 tissue levels depend both on exogenous dietetic intake and on endogenous biosynthesis, as this compound can be partly synthesized in human cells. Q10 plasma levels reflect the tissue content of the coenzyme and can be used to evaluate the presence of this compound in the human organism.

DESIGN/METHODS

Aim of the study was to measure CoQ10 plasmatic levels in a newborn breast-fed population and to compare them to CoQ10 levels in a newborn formula-fed population in order to verify whether changes in CoQ10 plasmatic contents could be related to a different dietetic intakes. We measured CoQ10 plasmatic levels in 25 healthy term neonates with different dietetic intakes: 15 breast-fed and 10 bottle-fed with a common infant formula. These infants were evaluated prospectively during the first month of life. The analyses were performed on the mothers' blood samples and cord blood samples at the time of delivery, then on infants at 4 and 28 days of age.

RESULTS

Our results showed markedly reduced Q10 levels in cord blood samples compared to maternal Q10 plasmatic levels at the time of delivery, suggesting placental impermeability towards this molecule or increased fetal utilization during labor and delivery. At 4 days of age Q10 levels had increased in both groups of neonates, but significantly more in breast-fed infants compared to formula-fed babies (p <0.05). At 4 weeks of age no significant changes occurred in breast-fed infants, while values increased significantly in formula-fed infants (p <0.05). The content of Q10 in breast milk samples was lower than in infant formula.

CONCLUSIONS

The results of this study show that CoQ10 plasmatic levels are at least partly influenced by the exogenous dietetic supply.

Coenzyme Q10 in patients with end-stage heart failure awaiting cardiac transplantation: a randomized, placebo-controlled study

BACKGROUND

The number of patients awaiting heart transplantation is increasing in proportion to the waiting period for a donor. Studies have shown that coenzyme Q10 (CoQ10) has a beneficial effect on patients with heart failure.

HYPOTHESIS

The purpose of the present double-blind, placebo-controlled, randomized study was to assess the effect of CoQ10 on patients with end-stage heart failure and to determine if CoQ10 can improve the pharmacological bridge to heart transplantation.

METHODS

A prospective double-blind design was used. Thirty-two patients with end-stage heart failure awaiting heart transplantation were randomly allocated to receive either 60 mg U/day of Ultrasome--CoQ10 (special preparation to increase intestinal absorption) or placebo for 3 months. All patients continued their regular medication regimen. Assessments included anamnesis with an extended questionnaire based partially on the Minnesota Living with Heart Failure Questionnaire, 6-min walk test, blood tests for atrial natriuretic factor (ANF) and tumor necrosis factor (TNF), and echocardiography.

RESULTS

Twenty-seven patients completed the study. The study group showed significant improvement in the 6-min walk test and a decrease in dyspnea, New York Heart Association (NYHA) classification, nocturia, and fatigue. No significant changes were noted after 3 months of treatment in echocardiography parameters (dimensions and contractility of cardiac chambers) or ANF and TNF blood levels.

CONCLUSIONS

The administration of CoQ10 to heart transplant candidates led to a significant improvement in functional status, clinical symptoms, and quality of life. However, there were no objective changes in echo measurements or ANF and TNF blood levels. Coenzyme Q10 may serve as an optional addition to the pharmacologic armamentarium of patients with end-stage heart failure. The apparent discrepancy between significant clinical improvement and unchanged cardiac status requires further investigation.

Sensitive and selective analysis of coenzyme Q10in human serum by negative APCI LC-MS

Two new sensitive and selective LC-MS methods have been developed for the quantification of the total coenzyme Q(10) concentration in human blood serum. The sensitivity of the methods is based on the very efficient formation of the radical anions of CoQ(10)[M(-)[radical dot]] by negative atmospheric pressure ionisation, APCI(-). The mass detection of the [M(-)[radical dot]] ions, m/z= 862.6, was performed either in selective ion monitoring (SIM) or in MS(2) mode (m/z= 862.6 [rightward arrow]m/z= 847.6) using an LCQ-deca ion-trap mass spectrometer. Two standard serum samples with medium (0.73 [micro sign]g ml(-1)) and high (1.96 [micro sign]g ml(-1)) total CoQ(10) concentrations were analysed by LC-APCI(-)-SIM and LC-APCI(-)-MS(2) and the results compared with a HPLC literature procedure with electrochemical detection (ECD). Both the LC-MS methods were shown to be more selective and with comparable or better sensitivity than the HPLC-ECD method. The LC-MS-SIM and LC-MS(2) chromatograms of the medium concentration sample showed CoQ(10) signal to noise ratios of 25 and 625, respectively. In addition, a simple and fast serum pre-treatment procedure was developed, in which the serum CoQ(10)H(2) content was quantitatively oxidised quantitatively to CoQ(10) in less than 15 min by 1,4-benzoquinone.

Relative bioavailability and antioxidant potential of two coenzyme q10 preparations

Coenzyme Q10 (CoQ10) is synthesized by the human body and found in certain foods. Daily supplementation of CoQ10 could protect against heart disease but the bioavailability of CoQ10 supplements depends on the formulation taken. We compared the bioavailability and antioxidant properties of two commercial CoQ10 formulations, a commercial grade CoQ10 powder (commercial grade CoQ) and a new BT-CoQ10 BIO-TRANSFORMED (BT-CoQ10) obtained by fermentation of a soy-based, CoQ10-rich media with baker's yeast. Eleven healthy individuals participated in a randomized two-way crossover trial, with a 3-week washout period. Capsules containing 300 mg of either BT-CoQ10 or commercial grade CoQ10 were given daily for 1 week and multiple blood samples were taken for CoQ10, glutathione and glutathione peroxidase (GPx) determination. In 3 subjects, baseline plasma CoQ10 levels were lower prior to BT than prior to commercial grade CoQ treatment. In the remaining participants, ingestion of BT vs. commercial grade CoQ significantly increased maximum plasma CoQ10 concentration (+126%, p = 0.04) and tended to increase CoQ10 area under the curve from 0 to 24 h (+160%, p = 0.07). One week of treatment with each formulation increased plasma CoQ10 but did not alter plasma glutathione or GPx activity. The enhanced bioavailability of the BT product might be due to its predominantly reduced, hydrophilic membrane-complex form.

Total coenzyme Q10 concentrations in Asian men following multiple oral 50-mg doses administered as coenzyme Q10 sustained release tablets or regular tablets

Coenzyme Q(10) (CoQ(10)), a highly lipophilic compound present in the inner mitochondrial membrane, is essential for production of cellular energy in the form of ATP. CoQ(10) is used as a dietary supplement and for treatment of various cardiovascular disorders. Our goal was to compare the CoQ(10) levels in Asians following multiple oral doses administered as sustained release or regular tablets. Twenty healthy male volunteers (19-23 years old) were divided into two equal groups. Each subject in Group I received 50 mg oral doses of coenzyme Q(10) as sustained release tablets once a day for fifteen days, while subject in Group II received 50 mg doses of coenzyme Q(10) regular tablets. The CoQ(10) levels were measured by HPLC-UV (reverse phase ODS column, 10 microm, 250 x 4.6 mm; oven temperature 30 degrees C). Mobile phase was constituted by methanol-ethanol 9 : 1 v/v. Flow rate was 1.5 ml/min and UV detection was carried out at 275 nm. Coenzyme Q(9) was used as an internal standard. CoQ(10) baseline in the morning was 0.88+/-0.48 mg/l. Following 1 week 50 mg/d dosing of CoQ(10), plasma CoQ(10) concentrations increased to 1.85+/-1.03 mg/l for sustained release tablets and up to 1.37+/-0.74mg/l for regular tablets. The net increment proportion in AUC for sustained release and regular tablets were 148.26+/-176.56%, 102.57+/-130.00%, respectively. Both preparations significantly increased the systemic exposure when compared to endogenous baseline.

Assay of coenzyme Q(10) in plasma by a single dilution step

A new method is described for determining coenzyme Q(10) (CoQ(10)) in plasma. The method is based on oxidation of CoQ(10) in the sample by treating it with para-benzoquinone followed by extraction with 1-propanol and direct injection into the HPLC apparatus. This method achieves a linear detector response for peak area measurements over the concentration range of 0.05-3.47 microM. Diode array analysis of the peak was consistent with CoQ(10) spectrum. Supplementation of the samples with known amounts of CoQ(10) yielded a quantitative recovery of 96-98.5%; the method showed a level of quantitation of 1.23 nmol per HPLC injection (200 microl of propanol extract containing 33.3 microl of plasma). A correlation of r = 0.99 (P < 0.0001) was found with a reference electrochemical detection method. Within run precision showed a CV% of 1.6 for samples approaching normal values (1.02 microM). Day-to-day precision was also close to 2%.

Circadian and seasonal variation of endogenous ubiquinone plasma level

Coenzyme Q10 (CoQ10) or ubiquinone, a redox component of the mitochondrial electron transport chains, is a powerful antioxidant and membrane stabilizer that may prevent cellular damage during myocardial ischemia and reperfusion therapy. Coenzyme Q10 has been used primarily as an adjuvant therapy for some cardiomyopathies. However, one of the main problems in CoQ10 administration is the high variability of endogenous plasma and tissue levels, which seems to be dependent on several factors. This work explores temporal 24h and seasonal variation as well as gender and racial differences in endogenous plasma ubiquinone concentration. Coenzyme Q10 measurements (quantified by HPLC-UV) of 16 healthy volunteers were done during the daytime hours of activity beginning at 09:00h one day and ending at 09:00h the next day (13 different determinations) in two distinct months. April and October, of the year. A statistically significant circadian rhythm in plasma ubiquinone concentration that includes only the fundamental 24h component was demonstrated both in the April and October data. Furthermore, the time-point means of the ubiquinone concentration in the October study were invariably higher than those obtained in the April study. No statistically significant differences were found in CoQ10 concentration between male and female subjects, both in April and in October. In addition, racial differences were demonstrated; lower plasma ubiquinone levels were found in Caucasian compared to African subjects. However, the latter small group of subjects failed to demonstrate a circadian rhythm, neither in the April nor in the October analysis.

Preparation and in vitro characterization of a eutectic based semisolid self-nanoemulsified drug delivery system (SNEDDS) of ubiquinone: mechanism and progress of emulsion formation

The objectives of the present work were, first, to develop a self-nanoemulsified drug delivery system (SNEDDS) based on the eutectic properties of ubiquinone (CoQ10); and second, to study the progress of emulsion formation and drug release mechanisms by turbidimetry and droplet size analysis. Binary phase diagrams of CoQ10 with menthol and essential oils were constructed and used to develop the self-nanoemulsified formulation. Pseudo ternary phase diagram was constructed to identify the efficient self-emulsification region. Release mechanisms of the resultant formulas were quantified using turbidimetry in combination with dissolution studies. Turbidity time profiles revealed three distinctive regions: lag phase, plateau, and the pseudolinear phase. Lag phase was attributed to the liquid crystalline properties of the formula. Plateau turbidity was correlated with droplet size. Laser diffraction analysis revealed an average droplet diameter of 100 nm. Emulsification rate was obtained from the corrected slope of the pseudolinear phase of the profile. Stability of the formula was further evaluated using Fourier transform-infrared (FT-IR) attached to an attenuated total reflectance (ATR) accessory. The present study revealed a eutectic based semisolid self-emulsified delivery system that can overcome the drawbacks of the traditional emulsified systems such as low solubility and irreversible precipitation of the active drug in the vehicle with time.

Preparation and characterization of coenzyme Q10-Eudragit solid dispersion

A solid dispersion of Coenzyme Q10 and Eudragit L 100-55 was prepared using solvent evaporation method. Solid dispersion, physical mixture, and pure compound were then characterized using differential scanning calorimetry and powder x-ray diffraction. Solubility of CoQ10 in different surfactant media was measured, and a suitable dissolution medium was developed to compare the dissolution patterns of the solid dispersion, physical mixture, and the pure compound. Combining labrasol with different surfactants in dissolution media demonstrated an additive effect on CoQ10 solubility. The solubility of CoQ10 in a 4% Labrasol/2% Cremophor EL solution was 562 microg/ml, which was five times higher than the combined solubility in 5% Labrasol (91 microg/ml) and 5% Cremophor EL (7.8 microg/ml). Moderate change in the crystalline pattern of CoQ10 was observed, which was attributed to solvent displacement rather than the degree of crystallinity change. The dissolution test indicated that the in-vitro release of Coenzyme Q10 from its solid dispersion was much faster than its physical mixture, which in turn was faster than the pure drug. The amount of drug released in 12 hours from solid dispersion, physical mixture, and the pure drug was 100, 26.5 and 12.5% respectively. CoQ10 was photostable throughout the dissolution experiments.

Isoprenoid biosynthesis is not compromised in a Zellweger syndrome mouse model

Because several studies indicated that peroxisomes are important for the biosynthesis of isoprenoids, we wanted to investigate whether a reduced availability of isoprenoids could be one of the pathogenic factors contributing to the severe phenotype of the Pex5(-/-) mouse, a model for Zellweger syndrome. Total cholesterol was determined in plasma, brain and liver of newborn mice. In none of these tissues a significant difference was observed between Pex5(-/-) and wild type or heterozygous mice. The hepatic ubiquinone content was found to be even higher in Pex5(-/-) mice as compared to wild type or heterozygous littermates. To investigate whether the Pex5(-/-) fetuses are able to synthesise their own isoprenoids, fibroblasts derived from these mice were incubated with radiolabeled mevalonolactone as a substrate for isoprenoid synthesis. No significant difference was observed between the cholesterol production rates of Pex5(-/-) and normal fibroblasts. Our results show that there is no deficiency of isoprenoids in newborn Pex5(-/-) mice, excluding the possibility that a lack of these compounds is a determinant factor in the development of the disease state before birth.

HPLC Analysis of Reduced and Oxidized Coenzyme Q10 in Human Plasma

Background: The percentage of reduced coenzyme Q10 (CoQ10H2) in total coenzyme Q10 (TQ10) is decreased in plasma of patients with prematurity, hyperlipidemia, and liver disease. CoQ10H2 is, however, easily oxidized and difficult to measure, and therefore reliable quantification of plasma CoQ10H2 is of clinical importance.

Methods: Venous blood was collected into evacuated tubes containing heparin, which were immediately placed on ice and promptly centrifuged at 4 °C. The plasma was harvested and stored in screw-top polypropylene tubes at −80 °C until analysis. After extraction with 1-propanol and centrifugation, the supernatant was injected directly into an HPLC system with coulometric detection.

Results: The in-line reduction procedure permitted transformation of CoQ10 into CoQ10H2 and avoided artifactual oxidation of CoQ10H2. The electrochemical reduction yielded 99% CoQ10H2. Only 100 μL of plasma was required to simultaneously measure CoQ10H2 and CoQ10 over an analytical range of 10 μg/L to 4 mg/L. Intra- and interassay CVs for CoQ10 in human plasma were 1.2–4.9% across this range. Analytical recoveries were 95.8–101.0%. The percentage of CoQ10H2 in TQ10 was ∼96% in apparently healthy individuals. The method allowed analysis of up to 40 samples within an 8-h period.

Conclusions: This optimized method for CoQ10H2 analysis provides rapid and precise results with the potential for high throughput. This method is specific and sufficiently sensitive for use in both clinical and research laboratories.

Plasma coenzyme Q(10) in children and adolescents undergoing doxorubicin therapy

The objective of this study was to test the hypothesis that doxorubicin treatment for cancer in childhood and adolescence causes a dose-related decrease in the concentration of plasma coenzyme Q(10). The concentration of plasma coenzyme Q(10) was measured before and after administration of doxorubicin in six patients, and before and after chemotherapy in six patients undergoing treatments that did not include doxorubicin. There was a significant increase in the concentration of plasma coenzyme Q(10) in post-treatment samples compared to pre-treatment samples in patients treated with doxorubicin (P=0.008; n=32), whereas there were no significant changes in plasma coenzyme Q(10) concentrations in patients treated with chemotherapy that did not include doxorubicin. (P=0.770; n=30). We hypothesise that the increase in plasma coenzyme Q(10) that was observed in patients undergoing doxorubicin treatment is due to release of coenzyme Q(10) from apoptotic or necrotic cardiac tissue. We conclude that the cardiotoxicity due to doxorubicin therapy does not involve acute myocardial depletion of coenzyme Q(10).