scholarly journals Development of a method for the measurement of dehydroepiandrosterone sulphate by liquid chromatography-tandem mass spectrometry

2005 ◽  
Vol 42 (6) ◽  
pp. 468-474 ◽  
Author(s):  
C A Chadwick ◽  
L J Owen ◽  
B G Keevil
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Lower Limit ◽  
Internal Standard ◽  
Tandem Mass ◽  
Dehydroepiandrosterone Sulphate ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Background: Dehydroepiandrosterone sulphate (DHEAS) is a steroid that is increasingly being recognized as a potential drug of abuse in many countries. This is due to its reputation as a hormone that may be able to retard the ageing process. The measurement of DHEAS is useful in the diagnosis of medical conditions such as congenital adrenal hyperplasia and polycystic ovary syndrome. Thus, a liquid chromatography-tandem mass spectrometry method has been developed to determine DHEAS concentrations in human serum. Method: The chromatography was performed using a WatersTM 2795 Alliance HT LC system coupled to a Mercury Fusion-RP column fitted with a SecurityGuardTM column. Results: DHEAS and the internal standard, deuterated DHEAS, both had a retention time of 1.5 min. The transition determined by the Micromass QuattroTM tandem mass spectrometer for DHEAS was m/z 367.3>96.7 and for the internal standard m/z 369.3>96.6. The method was linear up to 20 µmol/L; the lower limit of detection and the lower limit of quantitation were both 1 µmol/L. The intra- and interassay imprecision were <11% over a concentration range of 1-18 µmol/L for the in-house quality control and <12% for the intra- and interassay imprecision for the Bio-Rad Lyphocheck QC. Conclusion: The measurement of DHEAS by liquid chromatography-tandem mass spectrometry is robust and has a simple sample preparation procedure with a rapid cycle time of only 4 min.

Prednisolone measurement in human serum using liquid chromatography tandem mass spectrometry

2005 ◽  
Vol 42 (2) ◽  
pp. 105-111 ◽  
Author(s):  
LJ Owen ◽  
S Gillingwater ◽  
BG Keevil
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Lower Limit ◽  
Internal Standard ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
High Doses

Prednisolone is a commonly prescribed corticosteroid used in the treatment of many diseases. Despite high doses of prednisolone, some patients appear to have subtherapeutic concentrations of the drug. It would be useful to measure prednisolone in this group to determine if they have poor absorption or compliance. Hence, we have developed a liquid chromatography-tandem mass spectrometry method for the determination of prednisolone in serum. Chromatography was performed using a C18 column, giving a retention time for both prednisolone and deuterated prednisolone (internal standard) of 1.6 min. Two transitions were monitored for both prednisolone and deuterated prednisolone. These were m/z 361.2>343.0 and m/z 361.2>146.9 for prednisolone, and m/z 367.2>349.0 and m/z 367.2>149.9 for the internal standard. The intra- and inter-batch imprecision was <7% in both cases over a concentration range of 62.5-750 μg/L. The imprecision at the lower limit was 8%, the lower limit of quantitation was determined to be 30 μg/L and the method was linear up to 5000 μg/L. The method allows rapid prednisolone analysis because of a simplified sample extraction step, and has a cycle time of 3.5 min.

scholarly journals Evaluation of a rapid micro-scale assay for tacrolimus by liquid chromatography-tandem mass spectrometry

2002 ◽  
Vol 39 (5) ◽  
pp. 487-492 ◽  
Author(s):  
BG Keevil ◽  
SJ McCann ◽  
DP Cooper ◽  
MR Morris
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Immunosuppressive Drug ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Background: The immunosuppressive drug tacrolimus has complex and unpredictable pharmacokinetics, therefore regular monitoring is required in patients receiving tacrolimus therapy. We have developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring tacrolimus concentrations in whole blood and have compared it with a microparticle enzyme immunoassay. Methods: For the LC-MS/MS assay, samples were prepared in a 96-deep well microtitre plate by adding 10 µL of blood to 40 µL of 0·1 mol/L zinc sulphate solution. Proteins were precipitated by adding 100 µL acetonitrile containing ascomycin internal standard. After vigorous mixing and centrifugation, 20 µL of the supernatant was injected into the LC-MS/MS system. A C18 cartridge (3 mm × 4 mm) was eluted with a step gradient of 50% to 100% methanol containing 2 mmol/L ammonium acetate and 0·1% (v/v) formic acid, at 0·6 mL/min. The column was maintained at 55°C. Results: The retention times were 0·98 min for ascomycin and 0·98 min for tacrolimus. Cycle time was 2·5 min, injection to injection. The analytes were monitored using a Quattro micro tandem mass spectrometer operated in multiple reaction monitoring mode using the following transitions: m/z821 > 768 (tacrolimus) and m/z809 > 756 (ascomycin). The limit of quantitation was 0·5 µg/L and the assay was linear up to 30 µg/L. Precision of the method, over the concentration range 2·5-15·0 µg/L, was < 7% within-batch and < 6% between-batch. Total time to analyse 24 samples including result generation was 90 min. Conclusion: We conclude that the LC-MS/MS method is quick, precise and robust and will provide a fast turn around of results for the transplant physician.

scholarly journals Liquid Chromatography-Tandem Mass Spectrometry of Desoxo-Narchinol a and Its Pharmacokinetics and Oral Bioavailability in Rats and Mice

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2037 ◽  
Author(s):  
Subindra Kazi Thapa ◽  
Mahesh Upadhyay ◽  
Tae Hwan Kim ◽  
Soyoung Shin ◽  
Sung-Joo Park ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Oral Bioavailability ◽  
Internal Standard ◽  
Rat Plasma ◽  
Tandem Mass ◽  
Mouse Plasma ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Desoxo-narchinol A is one of the major active constituents from Nardostachys jatamansi, which has been reported to possess various pharmacological activities, including anti-inflammatory, antioxidant, and anticonvulsant activity. A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of desoxo-narchinol A in two different biological matrices, i.e., rat plasma and mouse plasma, using sildenafil as an internal standard (IS). The method involved simple protein precipitation with acetonitrile and the analyte was separated by gradient elution using 100% acetonitrile and 0.1% formic acid in water as a mobile phase. The MS detection was performed with a turbo electrospray in positive ion mode. The lower limit of quantification was 10 ng/mL in both rat and mouse plasma. Intra- and inter-day accuracies were in the ranges of 97.23–104.54% in the rat plasma and 95.90–110.11% in the mouse plasma. The precisions were within 8.65% and 6.46% in the rat and mouse plasma, respectively. The method was applied to examine the pharmacokinetics of desoxo-narchinol A, and the oral bioavailability of desoxo-narchinol A was 18.1% in rats and 28.4% in mice. The present results may be useful for further preclinical and clinical studies of desoxo-narchinol A.

scholarly journals A Hydrophilic Interaction Liquid Chromatography–Tandem Mass Spectrometry Quantitative Method for Determination of Baricitinib in Plasma, and Its Application in a Pharmacokinetic Study in Rats

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1600 ◽  
Author(s):  
Essam Ezzeldin ◽  
Muzaffar Iqbal ◽  
Yousif A. Asiri ◽  
Azza A Ali ◽  
Prawez Alam ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Janus Kinase ◽  
Pharmacokinetic Studies ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Baricitinib, is a selective and reversible Janus kinase inhibitor, is commonly used to treat adult patients with moderately to severely active rheumatoid arthritis (RA). A fast, reproducible and sensitive method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of baricitinib in rat plasma has been developed. Irbersartan was used as the internal standard (IS). Baracitinib and IS were extracted from plasma by liquid–liquid extraction using a mixture of n-hexane and dichloromethane (1:1) as extracting agent. Chromatographic separation was performed using Acquity UPLC HILIC BEH 1.7 µm 2.1 × 50 mm column with the mobile phase consisting of 0.1% formic acid in acetonitrile and 20 mM ammonium acetate (pH 3) (97:3). The electrospray ionization in the positive-mode was used for sample ionization in the multiple reaction monitoring mode. Baricitinib and the IS were quantified using precursor-to-production transitions of m/z 372.15 > 251.24 and 429.69 > 207.35 for baricitinib and IS, respectively. The method was validated according to the recent FDA and EMA guidelines for bioanalytical method validation. The lower limit of quantification was 0.2 ng/mL, whereas the intra-day and inter-day accuracies of quality control (QCs) samples were ranged between 85.31% to 89.97% and 87.50% to 88.33%, respectively. Linearity, recovery, precision, and stability parameters were found to be within the acceptable range. The method was applied successfully applied in pilot pharmacokinetic studies.

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