Simultaneous determination of some antidepressant drugs and vitamin B12 in pharmaceutical products and urine sample using HPLC method.

Three sensitive, accurate and precise HPLC methods were devolved for the simultaneous determination of vilazodone HCl (VILHC), agomelatine (AGO) or duloxetine HCl (DULHC) and vitamin B12 (cyanocoblamine B12) in bulk, pharmaceutical dosage form and in urine samples. Both similar methods (I and II) were carried out using 0.04 M phosphate buffer (pH 7.0), acetonitrile and methanol in the ratio (30:30:40, v/v) as a mobile phase. Thermo BDS hypersil-C18 column, with 5 µm particle size and 250 × 4.5 mm dimensions, at flow rate 1.0 mL min-1 and UV detection at 277 nm at ambient temperature 25 °C were used. The retention times were 5.12 and 2.54 min for VILHC and vitamin B12, 4.98 and 2.53 min for AGO and vitamin B12, respectively, with linearity range from 0.001 to 200 µg mL-1. However, for the separation of DULHC and B12, UV detection at 230 nm and Agilent Eclipse XDA-C8 (150 × 4.5 mm, 5 µm) column, were used (method III). The retention time of DULHC and vitamin B12 was found to be 4.53 and 1.35 min, respectively, with linearity range from 0.0005 to 200 µg mL-1. The proposed methods were validated as per the ICH guideline with very low LOD and LOQ. The values of %RSD for precision was less than 2% and the value of % recovery were found to be 99.20-100.9% and 99.23-100.67% for determination of the drugs in pure and pharmaceutical formulations, respectively, for all methods confirming that the methods are precise, accurate and selective for separation and determination of VILHC, AGO or DULHC from B12 in tablets and in urine samples without any interference from each other or from common excipients.

The concomitant lower concentrations of vitamins B6, B9 and B12 may cause methylation deficiency in autistic children.

Autism spectrum disorder (ASD) is characterized by severe and persistent difficulties in social communication and social interaction at multiple levels. Recently, metabolic disorders have been associated with most cases of patients with ASD. The aim of this study was to investigate, through a new and more sophisticated mass technique, such as UHPLC-mass spectrometry (Q-exactive analyzer), alteration in metabolisms analyzing ASD children urine samples from children showing simultaneous vitamin B6, B9 and B12 deficiencies. This in order to study how these concurrent deficiencies may influence some phenotypic aspects of autistic disorder. Thus, urinary metabolic patterns specific to ASD were explored at an early age in 60 children with ASD, showing lower three vitamins levels, and 60 corresponding controls (age group 3-8, M: F=42:18). The results showed significant block of cystathionine formation with consequent accumulation of homocysteine. A lower glutathione levels (GSH), with reduction of essential intracellular reducing environment required for normal immune function, detoxification capacity and redox-sensitive enzyme activity. Increased concentration of 5-methyltetrahydrofolate, which leads to a lower availability of methyl group and significant decrease in urinary methionine and S-adenosyl-L-methionine (SAM) concentrations, the major methyl donor. The latter justify the well-known reduction in protein and DNA methylation reported in autistic children. As a final consideration, the concomitant deficiencies of all three B vitamins, recorded in a significant number of autistic children, suggests that intestinal dysbiosis in these patients may be the main cause of a reduction in their absorption, in addition to the genetic mutation of a specific gene.

Silicon nanoparticles synthesized using a microwave method and used as a label-free fluorescent probe for detection of VB12.

A simple and rapid detection strategy for vitamin B12 (VB12 ) was established based on label-free silicon quantum dots (SiQDs); the detection mechanism was additionally investigated. SiQDs were synthesized using a one-step microwave method, and their fluorescence was stronger than that synthesized using the hydrothermal method. SiQDs fluorescence was quenched using VB12 due to the inner filter effect (IFE), which was demonstrated using ultraviolet (UV) absorption spectra, fluorescence lifetime, transmission electron microscopy and zeta potential analysis. Subsequently, quercetin (Que) and doxorubicin (Dox) with absorption peaks that overlapped the excitation or emission peaks of SiQDs respectively were used as control groups to investigate the quenching mechanism. Results showed that quenching efficiency was related to the level of overlap between the adsorption peak of the quencher and the excitation or emission peaks of SiQDs. A greater level of overlap caused a higher quenching efficiency. Therefore, the sensitive quenching of VB12 for SiQDs was due to the synergistic effect of the synchronous overlap between the absorption peak of VB12 with the excitation and emission peaks of SiQDs. Fluorescence quenching efficiency increased linearly in the 0.5 to 16.0 µmol·L-1 VB12 concentration range, and the detection limit was 158 nmol·L-1 . In addition, SiQDs were applied to determine VB12 in tablets and human urine samples with satisfactory recoveries ranging from 97.7 to 101.1%.

Solid phase extraction with Polypyrrole nanofibers for simultaneously determination of three water-soluble vitamins in urine.

This paper put forward a prospective pre-cleanup method of packed-fiber solid phase extraction by using Polypyrrole (Ppy) electrospun nanofibers as the sorbent to simultaneously extract three water-soluble vitamins (i.e., folic acid, cyanocobalamin and riboflavin) in human urine. Primary extraction of target analytes was carried out by loading samples onto the column along with diphenylboronic acid 2-aminoethylester (DPBA) reagent, and then the column should be rinsed with DPBA solution for three times before eluting. The DPBA was innovatively applied as complexing reagent to retain as much of three analytes as possible on the column based on the multi interaction between three vitamins and the boronate affinity reagent, thus improving hydrophobicity of targets and adsorption efficiency through loading and rinsing steps. Under optimized conditions, sample concentration factor was five times with small amount of organic solvent consumed and recoveries between 84.9% to 125.4%, and the lowest detection limit (LOD) between 0.020 to 0.041 µg/mL were achieved. Finally, the urine samples from a group of healthy children were processed with the optimized method. It proved that the proposed method is applicable in the determination of urinary B-vitamins in big samples of people.

Determination of vitamin B12 in equine urine by liquid chromatography - inductively coupled plasma - mass spectrometry.

Regulating authorities in the racing industry have restricted the administration of potentially performance enhancing cobalt salts to horses. There are severe penalties for trainers presenting horses with elevated urine cobalt concentrations, and compliance is ensured via analysis of total urinary cobalt at thresholds of 100 µg/L. When cobalt is present as part of the cobalamin molecule it is not considered performance enhancing. This paper demonstrates that a horse can excrete a significant proportion of a commercially available vitamin B12 injection in urine without metabolic modification. A liquid chromatography - inductively coupled plasma - mass spectrometry (LC-ICP-MS) method is presented for urinary cobalt speciation. Given the serious nature surrounding performance enhancing drug offences, we conclude that presumptive positives identified by urine total cobalt measurements require further analysis to differentiate inorganic cobalt from vitamin B12.

Improved Extraction Repeatability and Spectral Reproducibility for Liquid Extraction Surface Analysis-Mass Spectrometry Using Superhydrophobic-Superhydrophilic Patterning.

A major problem limiting reproducible use of liquid extraction surface analysis (LESA) array sampling of dried surface-deposited liquid samples is the unwanted spread of extraction solvent beyond the dried sample limits, resulting in unreliable data. Here, we explore the use of the Droplet Microarray (DMA), which consists of an array of superhydrophilic spots bordered by a superhydrophobic material giving the potential to confine both the sample spot and the LESA extraction solvent in a defined area. We investigated the DMA method in comparison with a standard glass substrate using LESA analysis of a mixture of biologically relevant compounds with a wide mass range and different physicochemical properties. The optimized DMA method was subsequently applied to urine samples from a human intervention study. Relative standard deviations for the signal intensities were all reduced at least 3-fold when performing LESA-MS on the DMA surface compared with a standard glass surface. Principal component analysis revealed more tight clusters indicating improved spectral reproducibility for a human urine sample extracted from the DMA compared to glass. Lastly, in urine samples from an intervention study, more significant ions (145) were identified when using LESA-MS spectra of control and test urine extracted from the DMA. We demonstrate that DMA provides a surface-assisted LESA-MS method delivering significant improvement of the surface extraction repeatability leading to the acquisition of more robust and higher quality data. The DMA shows potential to be used for LESA-MS for controlled and reproducible surface extraction and for acquisition of high quality, qualitative data in a high-throughput manner.

Prospective long-term evaluation of parenteral hydroxocobalamin supplementation in juvenile beagles with selective intestinal cobalamin malabsorption (Imerslund-Gräsbeck syndrome).

BACKGROUND: Prospective studies on maintenance treatment for Beagles with hereditary selective cobalamin (Cbl) malabsorption (Imerslund-Gräsbeck syndrome, IGS) are lacking. In our experience, measurement of methylmalonic acid (MMA), a Cbl-dependent metabolite, seems more helpful to monitor Cbl status as compared with serum Cbl concentrations. OBJECTIVES: To evaluate a standardized Cbl supplementation scheme in Beagles with IGS. We hypothesized that a single parenteral dose of 1 mg hydroxocobalamin (OH-Cbl) would maintain clinical and metabolic remission for up to 2 months. ANIMALS: Six client-owned juvenile Beagles with genetically confirmed IGS and 28 healthy control dogs. METHODS: Prospective study. Monthly IM OH-Cbl (1 mg) supplementation was done over a median of 9 months (range, 6-13) in 6 dogs, followed by bimonthly (every 2 months) injections in 5 dogs over a median of 6 months (range, 3-10). Health status was assessed by routine clinical examinations at injection time points and owner observations. Voided urine samples were collected immediately before OH-Cbl injections for measurement of MMA-to-creatinine concentrations using a gas-liquid chromatography-tandem mass spectrometry (GC-MS) method. RESULTS: All dogs were clinically healthy while receiving monthly and bimonthly OH-Cbl supplementation. Urinary MMA results in healthy dogs ranged from 1.3 to 76.5 mmol/mol creatinine (median, 2.9). Median urinary MMA concentrations did not differ between dogs with IGS receiving monthly (n = 49; 5.3 mmol/mol creatinine; range, 2.3-50.4) and bimonthly (n = 31; 5.3 mmol/mol creatinine; range, 1.6-50) injections. CONCLUSIONS AND CLINICAL IMPORTANCE: A maintenance parenteral dose of 1 mg OH-Cbl monthly or bimonthly appears adequate in Beagles with IGS monitored by metabolic testing.

Pharmacokinetics of inorganic cobalt and a vitamin B12 supplement in the Thoroughbred horse: Differentiating cobalt abuse from supplementation.

BACKGROUND: While cobalt is an essential micronutrient for vitamin B12 synthesis in the horse, at supraphysiological concentrations, it has been shown to enhance performance in human subjects and rats, and there is evidence that its administration in high doses to horses poses a welfare threat. Animal sport regulators currently control cobalt abuse via international race day thresholds, but this work was initiated to explore means of potentially adding to application of those thresholds since cobalt may be present in physiological concentrations. OBJECTIVES: To devise a scientific basis for differentiation between presence of cobalt from bona fide supplementation and cobalt doping through the use of ratios. STUDY DESIGN: Six Thoroughbred horses were given 10 mL vitamin B12 /cobalt supplement (Hemo-15® ; Vetoquinol, Buckingham, Buckinghamshire, UK., 1.5 mg B12 , 7 mg cobalt gluconate = 983 µg total Co) as an i.v. bolus then an i.v. infusion (15 min) of 100 mg cobalt chloride (45.39 mg Co) 6 weeks later. Pre-and post-administration plasma and urine samples were analysed for cobalt and vitamin B12 . METHODS: Urine and plasma samples were analysed for vitamin B12 using an immunoassay and cobalt concentrations were measured via ICP-MS. Baseline concentrations of cobalt in urine and plasma for each horse were subtracted from their cobalt concentrations post-administration for the PK analysis. Compartmental analysis was used for the determination of plasma PK parameters for cobalt using commercially available software. RESULTS: On administration of a vitamin B12 /cobalt supplement, the ratio of cobalt to vitamin B12 in plasma rapidly increased to approximately 3 and then rapidly declined below a ratio of 1 and then back to near baseline over the next week. On administration of 100 mg cobalt chloride, the ratio initially exceeded 10 in plasma and then declined with the lower 95% confidence interval remaining above a ratio of 1 for 7 days. For two horses with extended sampling, the plasma ratio remained above one for approximately 28 days after cobalt chloride administration. The effect of the administration of the vitamin B12 /cobalt supplement on the urine ratio was transient and reached a peak value of 10 which then rapidly declined. However, a urine ratio of 10 was exceeded, with the lower 95% confidence interval remaining above a ratio of 10 for 7 days after cobalt chloride administration. For the two horses with extended sampling, the urine ratio remained above 10 for about 18 days (442 h) after cobalt chloride administration even though the absolute cobalt urine concentration had dropped below the international threshold of 100 ng/mL after 96 h. MAIN LIMITATIONS: Only one vitamin B12 /cobalt product was evaluated, a limited number of horses were included, the horses were not in full race training and the results may be specific to this population of horses. CONCLUSIONS: The results provide the basis for a potential strategy for allowing supplementation with vitamin B12 products, while controlling the misuse of high doses of cobalt, through a combination of international thresholds and ratios of cobalt to vitamin B12 , in plasma and urine.

Quantification of chromatographic effects of vitamin B supplementation in urine and implications for hydration assessment.

Changes in body water elicit reflex adjustments at the kidney, thus maintaining fluid volume homeostasis. These renal adjustments change the concentration and color of urine, variables that can, in turn, be used as biomarkers of hydration status. It has been suggested that vitamin supplementation alters urine color; it is unclear whether any such alteration would confound hydration assessment via colorimetric evaluation. We tested the hypothesis that overnight vitamin B2 and/or B12 supplementation alters urine color as a marker of hydration status. Thirty healthy volunteers were monitored during a 3-day euhydrated baseline, confirmed via first morning nude body mass, urine specific gravity, and urine osmolality. Volunteers then randomly received B2 (n = 10), B12 (n = 10), or B2 + B12 (n = 10) at ∼200 × recommended dietary allowance. Euhydration was verified on trial days (two of the following: body mass ± 1.0% of the mean of visits 1-3, urine specific gravity < 1.02, urine osmolality < 700 mmol/kg). Vitamin purity and urinary B2 concentration ([B2]) and [B12] were quantified via ultraperformance liquid chromatography. Two independent observers assessed urine color using an eight-point standardized color chart. Following supplementation, urinary [B2] was elevated; however, urine color was not different between nonsupplemented and supplemented trials. For example, in the B2 trial, urinary [B2] increased from 8.6 × 10(4) ± 7.7 × 10(4) to 5.7 × 10(6) ± 5.3 × 10(6) nmol/l (P < 0.05), and urine color went from 4 ± 1 to 5 ± 1 (P > 0.05). Both conditions met the euhydrated color classification. We conclude that a large overnight dose of vitamins B2 and B12 does not confound assessment of euhydrated status via urine color.

Don't forget methylmalonic acid quantification in symptomatic exclusively breast-fed infants.

Vitamin B12 deficiency can lead to serious haematological and neurological signs in infants. The reported clinical cases of vitamin B12 deficiency were found in exclusively breast-fed infants whose asymptomatic mothers were diagnosed later with pernicious anaemia. For the infants, the diagnosis required urinary methylmalonic acid quantification (grossly elevated in these two cases) and treatment rapidly improved the clinical signs. These cases underline the serious consequences of vitamin B12 deficiency in infants and the helpful role of early methylmalonic acid quantification for diagnosis.

Three-month B vitamin supplementation in pre-school children affects folate status and homocysteine, but not cognitive performance.

BACKGROUND: Suboptimal vitamin B status might affect cognitive performance in early childhood. We tested the hypothesis that short-term supplementation with folic acid and selected B vitamins improves cognitive function in healthy children in a population with relatively low folate status. METHODS: We screened 1,002 kindergarten children for suboptimal folate status by assessing the total urinary para-aminobenzoylglutamate excretion. Two hundred and fifty low ranking subjects were recruited into a double blind, randomized, controlled trial to receive daily a sachet containing 220 µg folic acid, 1.1 mg vitamin B2, 0.73 mg B6, 1.2 µg B12 and 130 mg calcium, or calcium only for 3 months. Primary outcomes were changes in verbal IQ, short-term memory and processing speed between baseline and study end. Secondary outcomes were urinary markers of folate and vitamin B12 status, acetyl-para-aminobenzoylglutamate and methylmalonic acid, respectively, and, in a subgroup of 120 participants, blood folate and plasma homocysteine. RESULTS: Pre- and post-intervention cognitive measurements were completed by 115 children in the intervention and 122 in the control group. Compared to control, median blood folate increased by about 50% (P for difference, P < 0.0001). Homocysteine decreased by 1.1 µmol/L compared to baseline, no change was seen in the control group (P for difference P < 0.0001) and acetyl-para-aminobenzoylglutamate was 4 nmol/mmol higher compared to control at the end of the intervention (P < 0.0001). We found no relevant differences between the groups for the cognitive measures. CONCLUSION: Short-term improvement of folate and homocysteine status in healthy children does not appear to affect cognitive performance.

The soluble receptor for vitamin B12 uptake (sCD320) increases during pregnancy and occurs in higher concentration in urine than in serum.

BACKGROUND: Cellular uptake of vitamin B12 (B12) demands binding of the vitamin to transcobalamin (TC) and recognition of TC-B12 (holoTC) by the receptor CD320, a receptor expressed in high quantities on human placenta. We have identified a soluble form of CD320 (sCD320) in serum and here we present data on the occurrence of this soluble receptor in both serum and urine during pregnancy. METHODS: We examined serum from twenty-seven pregnant women (cohort 1) at gestational weeks 13, 24 and 36 and serum and urine samples from forty pregnant women (cohort 2) tested up to 8 times during gestational weeks 17-41. sCD320, holoTC, total TC and complex formation between holoTC and sCD320 were measured by in-house ELISA methods, while creatinine was measured on the automatic platform Cobas 6000. Size exclusion chromatography was performed on a Superdex 200 column. RESULTS: Median (range) of serum sCD320 increased from 125 (87-839) pmol/L (week 15) to reach a peak value of 199 (72-672) pmol/L (week 35) then dropped back to its baseline level just before birth (week 40). Around one third of sCD320 was precipitated with holoTC at all-time points studied. The urinary concentration of sCD320 was around two fold higher than in serum. Urinary sCD320/creatinine ratio correlated with serum sCD320 and reached a peak median level of 53 (30-101) pmol/mmol creatinine (week 35). sCD320 present in serum and urine showed the same elution pattern upon size exclusion chromatography. CONCLUSION: We report for the first time that sCD320 is present in urine and in a higher concentration than in serum and that serum and urine sCD320 increase during pregnancy. The high urinary concentration and the strong correlation between urinary and serum sCD320 suggests that sCD320 is filtered in the kidney.

Folate catabolites in spot urine as non-invasive biomarkers of folate status during habitual intake and folic acid supplementation.

BACKGROUND: Folate status, as reflected by red blood cell (RCF) and plasma folates (PF), is related to health and disease risk. Folate degradation products para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (apABG) in 24 hour urine have recently been shown to correlate with blood folate. AIM: Since blood sampling and collection of 24 hour urine are cumbersome, we investigated whether the determination of urinary folate catabolites in fasted spot urine is a suitable non-invasive biomarker for folate status in subjects before and during folic acid supplementation. STUDY DESIGN AND METHODS: Immediate effects of oral folic acid bolus intake on urinary folate catabolites were assessed in a short-term pre-study. In the main study we included 53 healthy men. Of these, 29 were selected for a 12 week folic acid supplementation (400 µg). Blood, 24 hour and spot urine were collected at baseline and after 6 and 12 weeks and PF, RCF, urinary apABG and pABG were determined. RESULTS: Intake of a 400 µg folic acid bolus resulted in immediate increase of urinary catabolites. In the main study pABG and apABG concentrations in spot urine correlated well with their excretion in 24 hour urine. In healthy men consuming habitual diet, pABG showed closer correlation with PF (rs = 0.676) and RCF (rs = 0.649) than apABG (rs = 0.264, ns and 0.543). Supplementation led to significantly increased folate in plasma and red cells as well as elevated urinary folate catabolites, while only pABG correlated significantly with PF (rs = 0.574) after 12 weeks. CONCLUSION: Quantification of folate catabolites in fasted spot urine seems suitable as a non-invasive alternative to blood or 24 hour urine analysis for evaluation of folate status in populations consuming habitual diet. In non-steady-state conditions (folic acid supplementation) correlations between folate marker (RCF, PF, urinary catabolites) decrease due to differing kinetics.

Development and validation of a liquid chromatography method for the simultaneous determination of eight water-soluble vitamins in multivitamin formulations and human urine.

A simple, precise, and rapid RPLC method has been developed without incorporation of any ion-pair reagent for the simultaneous determination of vitamin C (C) and seven B-complex vitamins, viz, thiamine hydrochloride (B1), pyridoxine hydrochloride (B6), nicotinamide (B3), cyanocobalamine (B12), folic acid, riboflavin (B2), and 4-aminobenzoic acid (Bx). Separations were achieved within 12.0 min at 30 degrees C by gradient elution on an RP C18 column using a mobile phase consisting of a mixture of 15 mM ammonium formate buffer and 0.1% triethylamine adjusted to pH 4.0 with formic acid and acetonitrile. Simultaneous UV detection was performed at 275 and 360 nm. The method was validated for system suitability, LOD, LOQ, linearity, precision, accuracy, specificity, and robustness in accordance with International Conference on Harmonization guidelines. The developed method was implemented successfully for determination of the aforementioned vitamins in pharmaceutical formulations containing an individual vitamin, in their multivitamin combinations, and in human urine samples. The calibration curves for all analytes showed good linearity, with coefficients of correlation higher than 0.9998. Accuracy, intraday repeatability (n = 6), and interday repeatability (n = 7) were found to be satisfactory.

Maximal load of the vitamin B12 transport system: a study on mice treated for four weeks with high-dose vitamin B12 or cobinamide.

Several studies suggest that the vitamin B12 (B12) transport system can be used for the cellular delivery of B12-conjugated drugs, also in long-term treatment Whether this strategy will affect the endogenous metabolism of B12 is not known. To study the effect of treatment with excess B12 or an inert derivative, we established a mouse model using implanted osmotic minipumps to deliver saline, cobinamide (Cbi) (4.25 nmol/h), or B12 (1.75 nmol/h) for 27 days (n = 7 in each group). B12 content and markers of B12 metabolism were analysed in plasma, urine, kidney, liver, and salivary glands. Both Cbi and B12 treatment saturated the transcobalamin protein in mouse plasma. Cbi decreased the content of B12 in tissues to 33-50% of the level in control animals but did not influence any of the markers examined. B12 treatment increased the tissue B12 level up to 350%. In addition, the transcript levels for methylenetetrahydrofolate reductase in kidneys and for transcobalamin and transcobalamin receptor in the salivary glands were reduced. Our study confirms the feasibility of delivering drugs through the B12 transport system but emphasises that B12 status should be monitored because there is a risk of decreasing the transport of endogenous B12. This risk may lead to B12 deficiency during prolonged treatment.

Selective extraction and determination of vitamin B12 in urine by ionic liquid-based aqueous two-phase system prior to high-performance liquid chromatography.

A rapid and simple extraction technique based on aqueous two-phase system (ATPS) was developed for separation and enrichment of vitamin B(12) in urine samples. The proposed ATPS-based method involves the application of the hydrophilic ionic liquid (IL) 1-hexyl-3-methylimidazolium chloride and K(2)HPO(4). After the extraction procedure, the vitamin B(12)-enriched IL upper phase was directly injected into the high performance liquid chromatography (HPLC) system for analysis. All variables influencing the IL-based ATPS approach (e.g., the composition of ATPS, pH and temperature values) were evaluated. The average extraction efficiency was 97% under optimum conditions. Only 5.0 mL of sample and a single hydrolysis/deproteinization/extraction step were required, followed by direct injection of the IL-rich upper phase into HPLC system for vitamin B(12) determination. A detection limit of 0.09 µg mL(-1), a relative standard deviation (RSD) of 4.50% (n=10) and a linear range of 0.40-8.00 µg mL(-1) were obtained. The proposed green analytical procedure was satisfactorily applied to the analysis of samples with highly complex matrices, such as urine. Finally, the IL-ATPS technique could be considered as an efficient tool for the water-soluble vitamin B(12) extraction.

A man with purple urine. Hydroxocobalamin-induced chromaturia.

In a clinical study, healthy subjects were given an antidote to a toxin that may be encountered by emergency physicians. Urine was collected for seven days following administration of the antidote. The drastic dark purple color of the urine on day 1, taken immediately after the antidote was given, is clearly of note.

Urinary excretion of vitamin B1, B2, B6, niacin, pantothenic acid, folate, and vitamin C correlates with dietary intakes of free-living elderly, female Japanese.

We hypothesized that 24-hour urinary excretion of water-soluble vitamins might correlate with their intake in free-living Japanese elderly females aged 70 to 84 years. We performed a cross-sectional study composed of 37 healthy, elderly, Japanese females living freely. All foods and the corresponding weights consumed for 4 consecutive days were recorded accurately. A 24-hour urine sample was collected on the fourth day, and the urinary content of water-soluble vitamins was measured. The urinary levels of all vitamins, except for B(12) (r = 0.01; P = .936), were correlated positively with the mean intake over the recent 4 days (vitamin B1: r = 0.62; P < .001; vitamin B2: r = 0.57; P < .001; vitamin B6: r = 0.37; P < .005; niacin: r = 0.54; P < .001; niacin equivalents: r = 0.54; P < .001; pantothenic acid: r = 0.59; P < .001; folate: r = 0.55; P = .001; and vitamin C: r = 0.53; P < .001). Mean estimated intakes of water-soluble vitamins calculated using urinary concentrations and recovery rates showed 96% to 107% of their 3-day mean intake, except for vitamin B12 (65%). We conclude that urinary levels of water-soluble vitamins, except for B12, reflected their recent intake in free-living Japanese elderly females and could be used as a measure of their intake during the previous few days both for group means and for individual rankings within a group.

Urinary excretion of vitamin B12 depends on urine volume in Japanese female university students and elderly.

Recent studies have shown that urinary excretion of water-soluble vitamins reflects their intake in humans. However, some have reported that physical characteristics and urine volume may affect the amount of vitamin compounds found in urine. We hypothesized that physical characteristics and urine volume could affect urinary excretion of B-group vitamins. Twenty-four-hour urine samples were collected from 186 free-living Japanese women aged 19 to 21 years and 104 free-living Japanese subjects aged 70 to 84 years. Correlations between urinary output of each B-group vitamin and body height, body weight, body mass index, body surface area, urine volume, and urinary creatinine were determined. Only urinary vitamin B(12) was strongly correlated to urine volume in young (r = 0.683, P < .001) and elderly (r = 0.523, P < .001) subjects. To confirm this finding, 20 Japanese adults were orally administered 1.5 mg of cyanocobalamin (500-fold higher daily intake); and correlations between urinary vitamin B(12) and urine volume were determined. The load of cyanocobalamin increased vitamin B(12) content in the urine by only 1.3-fold. Urinary vitamin B(12) was strongly correlated with urine volume on the day before taking, the day of taking, and the day after taking cyanocobalamin (r = 0.745, P < .001; r = 0.897, P < .0001; and r = 0.855, P < .0001, respectively). We conclude that urinary excretion of vitamin B(12) is dependent upon urine volume, but not on intake of vitamin B(12). Physical characteristics and urine volume are less important for B-group vitamins except for vitamin B(12) as biomarker.