Cost-Effective HPLC-UV Method for Quantification of Vitamin D2 and D3 in Dried Blood Spot: A Potential Adjunct to Newborn Screening for Prophylaxis of Intractable Paediatric Seizures

An HPLC-UV Method to Assess Human Plasma 25(OH)D3

The aim of this study was to validate an HPLC-UV method to assess vitamin D status by determining the linearity and precision of the 25-hydroxyvitamin D3 (25(OH)D3) calibration curve, the limits of detection, quantitation and robustness of the method, and its accuracy. A second stock solution of 25(OH)D3 was prepared (500 ng/mL), and working dilutions (5, 10, 20, 30, 40, and 50 ng/mL) were prepared for a calibration curve. The HPLC equipment had a UV-Vis diode-array detector and utilized an AcclaimTM 120 C18 column (5 µm, 4.6 × 250 mm) with a flow rate of 1.2 mL/min, a column temperature of 30 °C, and the standards and samples were maintained at 4 °C, with an injection volume of 100 µL. Detection of 25(OH)D3 was determined at 265 nm, with a retention time of 4.0 min. The validation was conducted according to the FDA Validation of Analytical Procedures: Guidance for Industry. Vitamin D was extracted from plasma samples using acetonitrile (ACN)-0.1% formic acid (2:1 v/v), and the percentage of recovery was calculated. The proposed method conditions gave excellent linearity (R2 = 0.9989) and the linearity coefficient was R2 > 0.99 for 25(OH)D3. The detection and quantification limits were 1.1703 ng/mL and 3.5462 ng/mL, respectively. Decreasing or increasing the reading temperature by 1 °C decreased the response units (AU) of vitamin D, 25(OH)D3. When the current flow rate decreased by 0.2 mL/min (1.0 mL/min), the retention time increased to 4.913 min, whereas an increase of 0.2 mL/min of the proposed flow rate (1.4 mL/min) decreased the retention time to 3.500 min. The percentage of recovery varied from 92.2% to 97.1%. The proposed method to quantify a vitamin D metabolite (25(OH)D3) in human plasma samples was reliable and validated.

Development of a Potential-Modulated Electrochemiluminescence Measurement System for Selective and Sensitive Determination of the Controlled Drug Codeine

Codeine is a common analgesic drug that is a pro-drug of morphine. It also has a high risk of abuse as a recreational drug because of its extensive distribution as an OTC drug. Therefore, sensitive and selective screening methods for codeine are crucial in forensic analytical chemistry. To date, a commercial analytical kit has not been developed for dedicated codeine determination, and there is a need for an analytical method to quantify codeine in the field. In the present work, potential modulation was combined with electrochemiluminescence (ECL) for sensitive determination of codeine. The potential modulated technique involved applying a signal to electrodes by superimposing an AC potential on the DC potential. When tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)3]2+) was used as an ECL emitter, ECL activity was confirmed for codeine. A detailed investigation of the electrochemical reaction mechanism suggested a characteristic ECL reaction mechanism involving electrochemical oxidation of the opioid framework. Besides the usual ECL reaction derived from the amine framework, selective detection of codeine was possible under the measurement conditions, with clear luminescence observed in an acidic solution. The sensitivity of codeine detection by potential modulated-ECL was one order of magnitude higher than that obtained with the conventional potential sweep method. The proposed method was applied to codeine determination in actual prescription medications and OTC drug samples. Codeine was selectively determined from other compounds in medications and showed good linearity with a low detection limit (150 ng mL-1).

Solutions for hematocrit bias in dried blood spot hormone analysis

Over the last years, dried blood spot (DBS) sampling has gained significant interest due to development of analytical techniques combined with DBS, the simplicity and low cost of the method. Despite its wide use, DBS sampling can lead to inaccurate results due to the impact of the hematocrit (Hct) on the analysis. Some analytes have shown to be hardly impacted by Hct values. However, in other cases, a significant impact of Hct is observed, which requires the use of alternative approaches to circumvent this issue. This review describes the possible impact of Hct-related bias in DBS sampling in the context of hormone analysis and discusses the different methodologies that can be used to overcome this bias to ensure accurate results.

Optimization of Very Low-Dose Formulation of Vitamin D3 with Lyophilizate for Dry Powder Inhalation System by Simple Method Based on Time-of-Flight Theory

It has been previously reported that active vitamin D3 (VD3) is a candidate drug that can repair alveolar damage in chronic obstructive pulmonary disease at a very low dose. We herein report the optimization of a very low-dose formulation of VD3 for dry powder inhalation by a simple method based on time-of-flight (TOF) theory. As the preparation content of VD3 is very low, aerodynamic particle size distribution cannot be measured by pharmacopeial methods that require quantification of the main drug. Thus, a simple method based on TOF theory, which can measure aerodynamic particle size distribution without quantification, was used. The optimized formulation for an inhalation system using a lyophilized cake contained phenylalanine as the excipient (VD3 1 μg/vial + phenylalanine 0.3 mg/vial) and showed high performance with fine particle fraction ≤ 3 μm = 47.2 ± 4.4%. The difference between the results of pharmacopeial methods and simple method was examined using the formulation containing 10 µg/vial of VD3 and was within 5.0%. The preparation is expected to efficiently deliver VD3 to the lungs. Our simple method can optimize dry powder inhalation formulations more easily and rapidly even when the content of the main drug in a preparation is very low.

Vitamin D status in women with dichorionic twin pregnancies and their neonates: a pilot study in China

Background

Vitamin D deficiency is a global public health issue in women and children and is associated with adverse impacts on child growth, such as rickets. However, prior studies have mainly focused on measuring vitamin D levels in singleton pregnant women and their offspring, and very limited studies have revealed the prevalence of vitamin D deficiency in twin pregnant women and their offspring. The aim of this study was to investigate vitamin D levels in twin-pregnant women and their neonates. We also explored the correlation of maternal vitamin D levels with neonatal outcomes and infant growth.

Methods

A prospective subcohort investigation was carried out among 72 dichorionic, diamniotic twin-pregnant mothers and their twin offspring from the Longitudinal Twin Study. Peripheral blood was collected from the mothers in the third trimester, and cord blood was collected from neonates at birth to identify 25[OH]D levels. Data on the characteristics of the mothers and neonates were collected. Infant growth data and food sensitivities were also collected.

Results

The average maternal 25[OH]D level was 31.78 ng/mL, with 19.4% being deficient and 20.8% insufficient, while the average neonatal 25[OH]D level was 15.37 ng/mL, with 99.3% being deficiency or insufficient. A positive correlation was found between maternal and neonatal 25[OH]D levels (beta-value: 0.43, 95% CI: 0.37, 0.49). Interestingly, the higher the maternal 25[OH]D level was, the smaller the cotwin birthweight discordance (beta-value: -2.67, 95% CI: − 5.11, − 0.23). In addition, the infants of mothers with vitamin D deficiency were more likely to be allergic to foods at 6 months than those of mothers with vitamin D sufficiency.

Conclusions

Twin neonates were at high risk of vitamin D deficiency, although their mothers’ vitamin D deficiency partially improved. Higher maternal vitamin D levels were associated with smaller discordance of cotwin birthweight.

Trial registration

Chinese Clinical Trial Registry ChiCTR-OOC-16008203, 1st April 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03707-7.

Selective, rapid and simultaneous determination of ergosterol and ergocalciferol in mushrooms by UPLC-Q-TOF-MS

An ultra-performance liquid chromatography coupled to atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry method has been optimized and validated for the determination of ergosterol and ergocalciferol in mushroom samples, using cholecalciferol as surrogate standard. The separation was carried out with a Synergi Hydro-RP column (100 mm x 3.00 mm i.d, 2.5 μm particle size), (Phenomenex, CA, USA) column, thermostated at 35 °C. The mobile phase was 0.1 % formic acid aqueous solution and methanol in gradient elution mode and it was achieved in 5 min approximately. Detection was achieved by atmospheric pressure chemical ionization in positive mode and quadrupole time-of-flight mass spectrometry. Desolvation and interface temperatures were set at 500 °C and 150 °C, respectively. The recoveries obtained were within 92-105 % for ergosterol, 77-81 % for ergocalciferol and 83-87 % for cholecalciferol. Method limits of detection were 0.4 and 0.5 μg g^-1 for ergosterol and ergocalciferol, respectively, and method limits of quantitation were 1.2 and 1.3 μg g^-1 for ergosterol and ergocalciferol, respectively. A rapid and simple extraction procedure using small amount of sample (100 mg) with hexane was optimized and the method was applied to the determination of ergosterol and ergocalciferol in white button mushrooms (Agaricus bisporus var. bisporus) exposed to UV irradiation. Results were compared to the corresponding non-irradiated mushrooms.

An efficient method for simultaneously screening for HIV, syphilis, and HCV based on one dried blood spot sample

OBJECTIVE

The aim of this study was to optimize the parameters of a dried blood spot (DBS)-based ELISA method to simultaneously screen for anti-HIV, anti-hepatitis C virus (HCV) and anti-treponema pallidum (TP) antibodies, and investigate the assay performance.

METHODS

Experiments were performed to establish optimized parameters for a DBS-based ELISA method to simultaneously screen for anti-HIV, anti-HCV, and anti-TP antibodies. Then, 429 paired plasma and DBS samples were collected to evaluate the performance of the assay with optimized parameters. Plasma test results were used as the reference standard.

RESULTS

The optimized assay conditions were: blood volume, 70-100 μL; DBS size, whole spot; eluent volume, 500 μL; eluent, PBS with 1‰ Tween20; elution time, 4 h; elution temperature, room temperature. The overall prevalence of HIV, HCV, and TP was 6.06% (95% confidence interval [CI]: 4.07-8.87%), 27.74% (95% CI: 23.60-32.28%), and 14.92% (95% CI: 11.75-18.73%). The clinical sensitivity of the assay for anti-HIV, anti-HCV, and anti-TP antibodies was 88.46%, 98.32%, and 92.19%, respectively. The assay was 100% specificity for each analyte. The assay positive predictive value for each analyte was 100%, and the negative predictive values were >98%. Of the 429 samples, 9 DBS results were different than the plasma results; in these samples the plasma signal-to-cutoff rations were low (range, 1.40-7.81).

CONCLUSION

The DBS-based ELISA method demonstrated good performance for simultaneously screening for anti-HIV, anti-HCV, and anti-TP antibodies. DBS samples are a promising method to screen for HIV, HCV, and TP infections.

IMPORTANCE

DBS samples are a promising alternative to plasma samples, with the advantages of good sample stability, smaller blood volume, simpler storage, and easier transport. DBS sample testing is used for the diagnosis of a wide variety of pathogens, including HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV). The performance of DBS samples for the serological diagnosis of HIV, HCV, and Treponema pallidum (TP) has been demonstrated to be good in many studies, and therefore DBS is regarded as an ideal choice to screen for HIV, HCV, and TP infections, especially in difficult-access or resource-limited settings. There is no generally accepted procedure for sample collection and processing of DBS samples and there are few studies on simultaneous detection of anti-HIV, anti-HCV and anti-TP using a single DBS.