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

Author(s):  
BG Keevil ◽  
SJ McCann ◽  
DP Cooper ◽  
MR Morris

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.

Author(s):  
C A Chadwick ◽  
L J Owen ◽  
B G Keevil

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.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1600 ◽  
Author(s):  
Essam Ezzeldin ◽  
Muzaffar Iqbal ◽  
Yousif A. Asiri ◽  
Azza A Ali ◽  
Prawez Alam ◽  
...  

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.


Author(s):  
LJ Owen ◽  
S Gillingwater ◽  
BG Keevil

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.


Author(s):  
DEEPAN T ◽  
BASAVESWARA RAO MV ◽  
DHANARAJU MD

Objective: A validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for canagliflozin in human plasma along with stability studies. Methods: The chromatographic separation of canagliflozin was performed on Zorbax XDB phenyl (75 × 4.6 mm, 3.5 mm) using methanol:acetate buffer (80:20 v/v) at a flow rate of 1.0 ml/min. The LC–MS/MS system consists of API 4000 triple quadrupole mass spectrometer equipped with turbospray ionization and an AS8020 automatic sample injector. Results: The retention time of canagliflozin was 1.15 min and total runtime was 2 min. The multiple reaction monitoring was 462.5/267.1 (m/z) for canagliflozin and 466.4/267.2 (m/z) for internal standard (canagliflozin D4), respectively. The method was linear over the range of 10–7505 ng/ml. The calculated slope ranged from 0.0451 to 0.0502 and intercepts from 0.0102 to 0.0456 with coefficients of the determination of 0.9970. The overall mean recovery of internal standard and canagliflozin was 76.66 and 79.77, respectively. Conclusion: The method was successfully validated and it was found to be within the limits for accuracy, precision, and linearity and it is stable under analytical conditions used.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yan Du ◽  
Hongliang Su ◽  
Jie Cao ◽  
Zhiwen Wei ◽  
Yujin Wang ◽  
...  

Male Sprague-Dawley rats (n=18) were randomly divided into three groups: a saline group (20 mL/kg by gavage), a ketamine (KET) group (100 mg/kg by gavage), and a KET (the same routes and doses) combined with levo-tetrahydropalmatine (l-THP; 40 mg/kg by gavage) group (n=6). Blood samples were acquired at different time points after drug administration. A simple and sensitive ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to determine the concentrations of KET and its metabolite, norketamine (NK), in rat plasma. Chromatographic separation was achieved using a BEH C18 column (2.1 mm×50 mm, 1.7 μm) with chlorpheniramine maleate (Chlor-Trimeton) as an internal standard (IS). The initial mobile phase consisted of acetonitrile–water with 0.1% methanoic acid (80 : 20, v/v). The multiple reaction monitoring (MRM) modes of m/z 238.1→m/z 179.1 for KET, m/z 224.1→m/z 207.1 for NK, and m/z 275→m/z 230 for Chlor-Trimeton (IS) were utilized to conduct a quantitative analysis. Calibration curves of KET and NK in rat plasma demonstrated good linearity in the range of 2.5–500 ng/mL (r>0.9994), and the lower limit of quantification (LLOQ) was 2.5 ng/mL for both. Moreover, the intra- and interday precision relative standard deviation (RSD) of KET and NK were less than 4.31% and 6.53%, respectively. The accuracies (relative error) of KET and NK were below -1.41% and -6.07%, respectively. The extraction recoveries of KET and NK were more than 81.23±3.45% and 80.42±4.57%, respectively. This sensitive, rapid, and selective UPLC-MS/MS method was successfully applied to study the pharmacokinetic effects of l-THP on KET after gastric gavage. The results demonstrated that l-THP could increase the bioavailability of KET and promote the metabolism of KET. The results showed that l-THP has pharmacokinetics effects on KET in rat plasma.


Author(s):  
David J Marshall ◽  
Joanne E Adaway ◽  
Brian G Keevil

Background Analysis of citrate and oxalate in a 24-h urine sample is important in the screening and monitoring of patients with nephrolithiasis. To streamline the analytical process, it was decided to combine oxalate and citrate and analyse them simultaneously in the same assay. Objective A highly sensitive and specific assay for analysis of urine citrate and oxalate was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a simple weak anion exchange solid phase extraction (WAX SPE) clean-up procedure. Method Premixed calibrator/acidified urine (50  µL) was combined with mixed internal standard (13C2 oxalate/citrate-d4) and 5% v/v formic acid in water and passed through a Waters WAX SPE plate. After clean-up steps, the plate was eluted with 5% NH3 in methanol, the eluent was dried down and re-constituted with 100  µL distilled water. Separation was then performed on an HSS T3 2.1 × 50 mm column (Waters, Manchester, UK), flow rate of 0.5 mL/min using a gradient of aqueous and organic mobile phases. We detected multiple reaction monitoring transitions m/z citrate 191.1>110.9, citrate IS 195.1>112.9, oxalate 88.9>60.85, oxalate IS 90.9>61.9 using a Waters TQD in electrospray-negative mode. Results Oxalate and 13C2 oxalate were eluted at 0.29 min; citrate and citrate-d4 were eluted at 0.52 min. Mean recovery was 100% for oxalate and 103% for citrate; lower limit of quantification of oxalate was 60  µmol/L and 50  µmol/L for citrate. Oxalate was linear up to 1388  µmol/L; citrate was linear up to 4762.5  µmol/L. Oxalate was found to be affected by ion suppression (matrix effect: −23 to +65%) but was compensated for by the internal standard used in all cases. The coefficient of variation of the assay in urine for oxalate was <7% for oxalate and 5% for citrate. Discussion We have developed a rapid assay for LC-MS/MS measurement of urinary oxalate and citrate in a routine clinical laboratory. It is simple, reproducible and easy to perform.


Metabolites ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 400
Author(s):  
Anas Al Aidaros ◽  
Charu Sharma ◽  
Claus-Dieter Langhans ◽  
Jürgen G. Okun ◽  
Georg F. Hoffmann ◽  
...  

This article reports a targeted metabolomic method for total plasma fatty acids (FAs) of clinical or nutritional relevance. Thirty-six saturated, unsaturated, or branched-chain FAs with a chain length of C8-C28 were quantified using reversed-phase liquid chromatography-tandem mass spectrometry. FAs in plasma (10 μL) were acid-hydrolyzed, extracted, and derivatized with DAABD-AE (4-[2-(N,N-Dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole) at 60 °C for 1 h. Derivatization resulted in a staggering nine orders of magnitude higher sensitivity compared to underivatized analytes. FAs were measured by multiple-reaction monitoring using stable isotope internal standards. With physiological and pathological analyte levels in mind, linearity was established using spiked plasma. Intra-day (n = 15) and inter-day (n = 20) imprecisions expressed as variation coefficient were ≤10.2% with recovery ranging between 94.5–106.4%. Limits of detection and limit of quantitation ranged between 4.2–14.0 and 15.1–51.3 pmol per injection, respectively. Age-stratified reference intervals were established in four categories: <1 month, 1–12 month, 1–18 year, and >18 year. This method was assessed using samples from patients with disorders affecting FAs metabolism. For the first time, C28:0 and C28:0/C22:0 ratio were evaluated as novel disease biomarkers. This method can potentially be utilized in diagnosing patients with inborn errors of metabolism, chronic disease risk estimation, or nutritional applications.


2020 ◽  
Vol 13 (2) ◽  
pp. 21
Author(s):  
Wisut Wichitnithad ◽  
Siriwan Nantaphol ◽  
Petploy Vicheantawatchai ◽  
Thanyaporn Kiatkumjorn ◽  
Wachirasak Wangkangwan ◽  
...  

This work demonstrated a sensitive, selective, and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitation of sumatriptan in human plasma samples. Terazosin was used as an internal standard to minimize the variability during sample processing and detection. Sample cleanup prior to chromatographic analysis was accomplished by liquid-liquid extraction (LLE) with tert-butyl methyl ether (t-BME). The separation was performed on a reversed-phase Symmetry® C18 column (150 × 4.6 mm i.d., 5 µm) under a gradient mode, using a 0.2% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min. Sumatriptan (m/z 296.26→251.05) and terazosin (m/z 388.10→290.25) were quantified using a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) under the positive ion mode. The method was fully validated following US-FDA and EMA guidelines. The LC-MS/MS assay had a calibration range of 0.5–50.0 ng/mL. The assay was precise and accurate with a between-run precision of <9.51%, and between-run accuracy between −7.27 to 8.30%. The developed method was subsequently applied in the determination of plasma concentration-time profile of a sumatriptan 50-mg tablet following oral administration in healthy volunteers.


2010 ◽  
Vol 61 (4) ◽  
pp. 381-388 ◽  
Author(s):  
Robert Roškar ◽  
Marija Dolenc

Determination of Benzodiazepines in Urine Via Benzophenone Derivatives Using Liquid Chromatography-Tandem Mass SpectrometryThe aim of this study was to validate a new method for determining benzodiazepines in urine via their benzophenone derivatives, based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). Selected benzodiazepines were analysed after acid hydrolysis of urine and extraction by ethyl acetate in the presence of an internal standard. Samples were analysed using electrospray ionization LC-MS/MS in a multiple reaction monitoring mode. The chromatographic run time on a reversed phase C18 analytical column was set for 9 min. This method was validated in 21 patients receiving methadone. Benzodiazepines intake was established in two out of three patients. LC-MS/MS results were also compared with the rapid immunoassay and the methods showed good agreement. However, in three cases benzodiazepines were detected by LC-MS/MS, but not by the immunoassay. The sensitivity of the developed LC-MS/MS method is comparable to or even higher than of previously reported methods, which makes it suitable as a confirmatory method.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yunliang Zheng ◽  
Xingjiang Hu ◽  
Jian Liu ◽  
Guolan Wu ◽  
Huili Zhou ◽  
...  

A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine blonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS) was established. A simple direct protein precipitation method was used for the sample pretreatment, and chromatographic separation was performed on a Waters XBridge C8(4.6×150 mm, 3.5 μm) column. The mobile phase consists of a mixture of 10 mM ammonium formate and 0.1% formic acid in water (A) and 0.1% formic acid in methanol (B). To quantify blonanserin, blonanserin C, and IS, multiple reaction monitoring (MRM) was performed in positive ESI mode. The calibration curve was linear in the concentration range of 0.012–5.78 ng·mL−1for blonanserin and 0.023–11.57 ng·mL−1for blonanserin C (r2>0.9990). The intra- and interday precision of three quality control (QC) levels in plasma were less than 7.5%. Finally, the current simple, sensitive, and accurate LC-MS/MS method was successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in healthy Chinese volunteers.


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