Ultra-fast cyclosporin A quantitation in whole blood by Laser Diode Thermal Desorption – Tandem Mass Spectrometry; comparison with High Performance Liquid Chromatography–Tandem Mass Spectrometry

CuBTC metal organic framework-based dispersive solid phase extraction of cyclosporine and tacrolimus from plasma samples prior to determination by high performance liquid chromatography-tandem mass spectrometry

Immunosuppressive drugs are prescribed to reduce the immune system of persons who are undergoing organ transplants. The concentration of these drugs in blood and plasma samples must be accurately and precisely determined during immunosuppressive therapy due to their significant side effects. In this study, a metal organic framework-based dispersive solid phase extraction method was developed for the extraction of tacrolimus and cyclosporine from plasma samples before their determination by high performance liquid chromatography-tandem mass spectrometry. For this purpose, CuBTC metal organic framework nanoparticles were prepared by a hydrothermal approach and they were used as the sorbent in the extraction procedure. The adsorbed analytes were eluted by a suitable organic solvent and then more concentrated by evaporation of the eluate. All of the effective parameters of the method including sorbent amount, adsorption time, eluent type, desorption time, eluent volume, and sample solution pH were studied and optimized. They were obtained 5 mg, 5 min, acetone, 5 min, 300 μL, and 5, respectively. Under optimal conditions, the developed method was validated and the data showed that the linear range, the limit of detection, the limit of quantification, the coefficient of determination, the enrichment factor, and relative standard deviation values were 1-1000 ng mL^-1, 0.30 ng mL^-1, 0.5 ng mL^-1, 0.99, 15.6, and 5.8 % for tacrolimus and 0.8-500 ng mL^-1, 0.25 ng mL^-1, 0.4 ng mL^-1, 0.99, 17, and 5.6 % for cyclosporine, respectively. Finally, the method was successfully used in the determination of the studied drugs in plasma samples.

Ultrafast analysis of peptides by laser diode thermal desorption-triple quadrupole mass spectrometry

RATIONALE

The COVID-19 pandemic demonstrated the importance of high-throughput analysis for public health. Given the importance of surface viral proteins for interactions with healthy tissue, they are targets of interest for mass spectrometry-based analysis. For that reason, the possibility of detecting and quantifying peptides using a high-throughput technique, laser diode thermal desorption-triple quadrupole mass spectrometry (LDTD-QqQMS), was explored.

METHODS

Two peptides used as models for small peptides (leu-enkephalin and endomorphin-2) and four tryptic peptides (GVYYPDK, NIDGYFK, IADYNYK, and QIAPGQTGK) specific to the SARS-CoV-2 Spike protein were employed. Target peptides were analyzed individually in the positive mode by LDTD-QqQMS. Peptides were quantified by internal calibration using selected reaction monitoring transitions in pure solvents and in samples spiked with 20 μg mL^-1 of a bovine serum albumin tryptic digest to represent real analysis conditions.

RESULTS

Low-energy fragment ions (b and y ions) as well as high-energy fragment ions (c and x ions) and some of their corresponding water or ammonia losses were detected in the full mass spectra. Only for the smallest peptides, leu-enkephalin and endomorphin-2, were [M + H]⁺ ions observed. Product ion spectra confirmed that, with the experimental conditions used in the present study, LDTD transfers a considerable amount of energy to the target peptides. Quantitative analysis showed that it was possible to quantify peptides using LDTD-QqQMS with acceptable calibration curve linearity (R²  > 0.99), precision (RSD < 18.2%), and trueness (bias < 8.3%).

CONCLUSIONS

This study demonstrated for the first time that linear peptides can be qualitatively and quantitatively analyzed using LDTD-QqQMS. Limits of quantification and dynamic ranges are still inadequate for clinical applications, but other applications where higher levels of proteins must be detected could be possible with LDTD. Given the high-throughput capabilities of LDTD-QqQMS (>15 000 samples in less than 43 h), more studies are needed to improve the sensitivity for peptide analysis of this technique.

Rapid screening procedures for a variety of complex forensic samples using laser diode thermal desorption (LDTD) coupled to different mass spectrometers

RATIONALE

The applications shared in this paper demonstrate the wide variety of samples that can be analyzed when Laser Diode Thermal Desorption (LDTD) is interfaced with a high-resolution mass spectrometer and show the speed at which high quality data can be generated from complex matrices.

METHODS

Samples are solvent extracted and spotted in a 96-well plate. In the case of biological fluids, hydrolysis followed by solid-phase extraction is required. The solvent in the 96-well plate is evaporated followed by mass spectrometric (MS) analysis with atmospheric pressure chemical ionization. Where applicable, the instrument is operated in data-dependent mode, with a full-scan mass spectrum followed by MS/MS spectra of the top 10 ions with a total runtime of 0.4 min.

RESULTS

Four applications (MAAQ and Tear Gas, twelve rodenticides, seven explosives, and 40 drugs of abuse) are reported in this paper. MAAQ, tear gas, and rodenticides were identified by full-scan, followed by MS/MS experiments at levels of 125 μg/L, 125 μg/L, and 500 μg/L, respectively. Explosives were all identified at 102 μg/L by full-scan experiments. The drugs of abuse were identified by multiple reaction monitoring (MRM) experiments at defined cutoff levels from 2 to 1000 μg/L.

CONCLUSIONS

Interfacing LDTD with a mass spectrometer allows for rapid screening of a wide range of samples, with either minimal or complex sample preparation. Using a high-resolution mass spectrometer with the combination to perform full-scan and MS/MS experiments adds a high level of specificity.

Mass spectrometry based high-throughput bioanalysis of low molecular weight compounds: are we ready to support personalized medicine?

Liquid chromatography coupled to mass spectrometry (LC-MS) is the gold standard in bioanalysis for the development of quantitative assays to support drug development or therapeutic drug monitoring. High-throughput and low-cost gene sequencing have enabled a paradigm shift from one treatment fits all to personalized medicine (PM). However, gene monitoring provides only partial information about the health state. The full picture requires the combination of gene monitoring with the screening of exogenous compounds, metabolites, lipids, and proteins. This critical review discusses how mass spectrometry–based technologies and approaches including separation sciences, ambient ionization, and ion mobility are/could be used to support high-throughput bioanalysis of endogenous end exogenous low molecular weight compounds. It includes also various biological sample types (from blood to expired air), and various sample preparation techniques.

Overview of therapeutic drug monitoring of immunosuppressive drugs: Analytical and clinical practices

Immunosuppressant drugs (ISDs) play a key role in short-term patient survival together with very low acute allograft rejection rates in transplant recipients. Due to the narrow therapeutic index and large inter-patient pharmacokinetic variability of ISDs, therapeutic drug monitoring (TDM) is needed to dose adjustment for each patient (personalized medicine approach) to avoid treatment failure or side effects of the therapy. To achieve this, TDM needs to be done effectively. However, it would not be possible without the proper clinical practice and analytical tools. The purpose of this review is to provide a guide to establish reliable TDM, followed by a critical overview of the current analytical methods and clinical practices for the TDM of ISDs, and to discuss some of the main practical aspects of the TDM.

LASER DESORPTION/ABLATION POSTIONIZATION MASS SPECTROMETRY: RECENT PROGRESS IN BIOANALYTICAL APPLICATIONS

Lasers have long been used in the field of mass spectrometric analysis for characterization of condensed matter. However, emission of neutrals upon laser irradiation surpasses the number of ions. Typically, only one in about one million analytes ejected by laser desorption/ablation is ionized, which has fueled the quest for postionization methods enabling ionization of desorbed neutrals to enhance mass spectrometric detection schemes. The development of postionization techniques can be an endeavor that integrates multiple disciplines involving photon energy transfer, electrochemistry, gas discharge, etc. The combination of lasers of different parameters and diverse ion sources has made laser desorption/ablation postionization (LD/API) a growing and lively research community, including two-step laser mass spectrometry, laser ablation atmospheric pressure photoionization mass spectrometry, and those coupled to ambient mass spectrometry. These hyphenated techniques have shown potentials in bioanalytical applications, with major inroads to be made in simultaneous location and quantification of pharmaceuticals, toxins, and metabolites in complex biomatrixes. This review is intended to provide a timely comprehensive view of the broadening bioanalytical applications of disparate LD/API techniques. We also have attempted to discuss these applications according to the classifications based on the postionization methods and to encapsulate the latest achievements in the field of LD/API by highlighting some of the very best reports in the 21st century. © 2020 John Wiley & Sons Ltd.

Sensitive, wide-range and high-throughput quantification of cyclosporine in whole blood using ultra-performance liquid chromatography coupled to tandem mass spectrometry and comparison with an antibody-conjugated magnetic immunoassay

Because either trough or peak concentration at 2 h after administration is measured in routine therapeutic drug monitoring for cyclosporine A (CyA), a quantification method with a wide-range calibration curve capable of simultaneously measuring both concentrations is required. We developed a sensitive, wide-range and high-throughput quantification method for CyA in whole blood using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and compared patients' blood CyA levels measured by UPLC-MS/MS and antibody-conjugated magnetic immunoassay (ACMIA). Whole blood samples were prepared by solid-phase extraction using Oasis HLB μElution plate. The UPLC-MS/MS assay showed excellent linearity over a wide calibration range of 5-2500 ng/mL. Within-batch accuracy and precision as well as batch-to-batch accuracy and precision fulfilled the criteria of US Food and Drug Administration guidelines. The blood CyA concentrations measured by the UPLC-MS/MS assay correlated strongly with those measured by ACMIA. A Bland-Altman plot showed a fixed error between CyA concentrations measured by the two methods, and the concentrations measured by the UPLC-MS/MS method were consistently lower than those measured by ACMIA. We have succeeded to develop a sensitive, wide-range and high-throughput quantification method for CyA in whole blood using UPLC-MS/MS.

Rapid determination of tacrolimus and sirolimus in whole human blood by direct coupling of solid-phase microextraction to mass spectrometry via microfluidic open interface

Immunosuppressive drugs are administered to decrease immune system activity (e.g. of patients undergoing solid organ transplant). Concentrations of immunosuppressive drugs (ISDs) in circulating blood must be closely monitored during the period of immunosuppression therapy due to adverse effects that take place when concentration levels fall outside of the very narrow therapeutic concentration range of these drugs. This study presents the rapid determination of four relevant immunosuppressive drugs (tacrolimus, sirolimus, everolimus, and cyclosporine A) in whole human blood by directly coupling solid-phase microextraction to mass spectrometry via the microfluidic open interface (Bio-SPME-MOI-MS/MS). The BioSPME-MOI-MS/MS method offers ≤ 10% imprecision of in-house prepared quality controls over a 10-day period, ≤ 10% imprecision of ClinCal® Recipe calibrators over a three-day period, and single total turnaround time of ∼ 60 min (4.5 min for high throughput). The limits of quantification were determined to be 0.8 ng mL^-1 for tacrolimus, 0.7 ng mL^-1 sirolimus, 1.0 ng mL^-1 for everolimus, and 0.8 ng mL^-1 for cyclosporine. The limits of detection were determined to be 0.3 ng mL^-1 for tacrolimus, 0.2 ng mL^-1 for sirolimus, 0.3 ng mL^-1 for everolimus, and 0.3 ng mL^-1 for cyclosporine A. The R² values for all analytes were above 0.9992 with linear dynamic range from 1.0 mL^-1 to 50.0 ng mL^-1 for tacrolimus, sirolimus, and everolimus while from 2.5 ng mL^-1 to 500.0 ng mL^-1 for cyclosporine A. To further evaluate the performance of the present method, 95 residual whole blood samples of tacrolimus and sirolimus from patients undergoing immunosuppression therapy were used to compare the Bio-SPME-MOI-MS/MS method against a clinically validated reference method based on chemiluminescent microparticle immunoassay, showing acceptable results. Our results demonstrated that Bio-SPME-MOI-MS/MS can be considered as a suitable alternative to existing methods for the determination of immunosuppressive drugs in whole blood providing faster analysis, better selectivity and sensitivity, and a wider dynamic range than current existing approaches.

Further studies on the signal enhancement effect in laser diode thermal desorption-triple quadrupole mass spectrometry using microwell surface coatings

The laser diode thermal desorption (LDTD) ionization source allows ultrafast and sensitive analysis of small molecules by mass spectrometry. Signal enhancement in LDTD has been observed when coating the surface of sample microwells with a solution of ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid. Here we present a quantitative analysis of signal enhancement using solutions of diverse commercial proteins (lysozyme, immunoglobulin G, albumin, and fibrinogen) as coatings. Results showed that compounds with polar chemical functions such as carboxylic acid, sulfonyl, and nitro had signal enhancement factors, in most cases higher than 10, when using any of the tested proteins as coating agent. Analysis of variance revealed that immunoglobulin G and fibrinogen gave the best results. However, the signal enhancement factors obtained with these proteins were not superior to those observed with EDTA. To explain the signal enhancement effect of proteins, analysis by scanning electron microscopy of dried samples on the microwell sample plates was carried out. Images showed that salicylic acid, one of the compounds with the highest observed signal enhancement, formed a thick layer when applied directly on the uncoated surface, but it formed small crystals (<1 μm) in the presence of protein or EDTA coatings. Further crystallographic studies using powder X-ray diffraction showed that the crystalline form of salicylic acid is modified in the presence of EDTA. Salicylic acid when mixed with EDTA had a higher percentage of amorphous phase (38.1%) than without EDTA (23.1%). These results appear to confirm that the diminution of crystal size of analytes and the increase of amorphous phase are implicated in signal enhancement effect observed in LDTD using microwell surface coatings. To design better coatings and completely elucidate the signal enhancement effect in LDTD, more studies are necessary to understand the effects of coatings on the ionization of analytes.

A 6 Second Analytical Method for Quantitation of Tacrolimus in Whole Blood by Use of Laser Diode Thermal Desorption Tandem Mass Spectrometry

BACKGROUND

Therapeutic drug monitoring of immunosuppressive drugs is imperative for organ transplant recipients. High-performance LC-MS/MS is considered gold standard; however, immunoassays provide rapid turnaround time. New technology was developed to reduce mass spectrometry analytical run-time. The laser diode thermal desorption source coupled with tandem mass spectrometry (LDTD-MS/MS) eliminates chromatographic separation to increase analytical throughput.

METHODS

A rapid, 6 second, LDTD-MS/MS analytical method was developed for the quantification tacrolimus in whole blood. Whole blood samples were lysed, followed by protein precipitation and solid-phase extraction. Extracted samples with desorption solution were spotted onto a LazWell plate then dried and loaded into the LDTD source for analysis with an AB SCIEX 5500 mass spectrometer in positive multiple reaction monitoring mode. The LDTD laser profile ramps from 0% to 65% of full power over 3 s and is held at 65% for 1 s before returning to initial conditions for 2 s.

RESULTS

Data presented include tacrolimus by LDTD-MS/MS comparison to LC-MS/MS, sensitivity, imprecision, interference, linearity, and stability. Method comparison between LDTD-MS/MS and a validated in-house LC-MS/MS assay yielded the following: (LDTD-MS/MS) = 1.119 (LC-MS/MS) + 0.23 ng/mL, S_y/x = 1.26, r = 0.9871 (n = 122). The limit of quantification by LDTD-MS/MS for tacrolimus was <0.3 ng/mL and total imprecision was <10%.

CONCLUSIONS

Laser diode thermal desorption tandem mass spectrometry technology can provide rapid turnaround time to result for tacrolimus. The analytical time for LDTD-MS/MS was 6 s compared to 135 s by LC-MS/MS, a >95% decrease in analytical time.

Signal enhancement in laser diode thermal desorption-triple quadrupole mass spectrometry analysis using microwell surface coatings

Laser-diode thermal desorption (LDTD) is an ionization source usually coupled to triple quadrupole mass spectrometry (QqQMS) and specifically designed for laboratories requiring high-throughput analysis. It has been observed that surface coatings on LDTD microwell plates can improve the sensitivity of the analysis of small polar molecules. The objective of the present study is to understand and quantify the effect of microwell surface coatings on signal intensity of small organic molecules of clinical, environmental, and forensic interest. Experiments showed that the peak areas of diclofenac, chloramphenicol, salicylic acid, and 11-nor-9-carboxy-Δ⁹ -tetrahydrocannabinol obtained by LDTD-QqQMS increased by up to 3 orders of magnitude when using microwells coated with ethylenediaminetetraacetic acid (EDTA). Tests with different chelating agents and polytetrafluoroethylene as microwell surface coatings showed that nitrilotriacetic acid gave significantly higher peak areas for five out of the nine compounds that showed signal enhancement using chelating agents as coatings. Scanning electron microscopy studies of EDTA-coated and uncoated microwells showed that analytes deposited in the former formed more uniform and thinner films than in the latter. The enhancement effect of surface coatings in LDTD-QqQMS was explained mainly by the formation of homogenous and thinner layers of nanocrystals of analytes that are easier to desorb thermally than the layers formed when the analytes dry in direct contact with the bare stainless-steel surface. Chemisorption of some analytes to the stainless-steel surface of the microwell plate appeared to be a minor factor. Surface coatings widen the number of compounds analyzable by LDTD-QqQMS and can also improve sensitivity and limits of detection.

Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry for Cyclosporine Analysis in Human Whole Blood and Comparison With an Antibody-Conjugated Magnetic Immunoassay

BACKGROUND

Various immunoassays have been used for cyclosporine A (CsA) analysis in human whole blood; however, they could not fully satisfy the requirements of criteria for accuracy and specificity in CsA measurement. The liquid chromatography tandem mass spectrometry is a gold method for CsA analysis. The aim of the study was to develop and validate an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for CsA analysis and establish its agreement with an antibody-conjugated magnetic immunoassay (ACMIA) in clinical sample analysis.

METHODS

An UHPLC-MS/MS method for CsA analysis in human whole blood was developed, validated, and applied in 85 samples, which were also tested by ACMIA. The agreement between UHPLC-MS/MS and ACMIA was evaluated by Bland-Altman plot.

RESULTS

The calibration range was 5-2000 ng/mL. The inaccuracy and imprecision were -4.60% to 5.56% and less than 8.57%, respectively. The internal standard-normalized recovery and matrix factor were 100.4%-110.5% and 93.5%-107.6%, respectively. The measurements of ACMIA and UHPLC-MS/MS were strongly correlated (r > 0.98). Evaluated by Bland-Altman plot, the 95% limit of agreement of the ACMIA:UHPLC-MS/MS ratio was 88.7%-165.6%, and the mean bias of the ratio was 21.1%.

CONCLUSIONS

A rapid, simple, accurate, and reliable UHPLC-MS/MS method for CsA analysis in human whole blood was developed, validated, and applied in 85 samples. On average, 21.1% overestimation was observed in ACMIA compared with that in the UHPLC-MS/MS. Further and larger studies are required to identify whether this degree of variance could be accepted by clinicians.

Immunologic Monitoring to Personalize Immunosuppression After Liver Transplant

Although immunosuppressive drugs have enhanced patient outcomes in transplantation, the liver transplant community has made significant research efforts into the discovery of more accurate and precise methods of posttransplant monitoring and diagnosing. Current research in biomarkers reveals many promising approaches.

Simultaneous determination of cyclosporine and tacrolimus in human whole blood by ultra-high performance liquid chromatography tandem mass spectrometry and comparison with a chemiluminescence microparticle immunoassay

Overestimation of immunoassays for cyclosporine (CsA) and tacrolimus (TAC) analysis in human whole blood is a problem. The liquid chromatography tandem mass spectrometry is recommended as a golden method for CsA and TAC analysis. The aim of the study is to develop and validate an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of CsA and TAC in human whole blood and evaluate its agreement with a chemiluminescence microparticle immunoassay (CMIA). The UHPLC-MS/MS method for simultaneous determination of CsA and TAC in human whole blood was developed and validated according to the guidelines. A total of 177 CsA and 220 TAC samples were determined by UHPLC-MS/MS and CMIA, and the agreement of the two methods was evaluated by Bland-Altman plot. The calibration range of UHPLC-MS/MS method was 5 to 2000 ng/mL for CsA and 0.2 to 80 ng/mL for TAC. The inaccuracy and imprecision were -13.33% to 11.80% and <11.74% for CsA and -8.94% to 6.53% and <10.84% for TAC, respectively. Evaluated by Bland-Altman plot, the mean overestimation of CMIA compared to UHPLC-MS/MS was 53.7% for CsA and 48.1% for TAC.

Ultrafast quantitative MS-based method for ceritinib analysis in human plasma samples from clinical trial

Aim: An ultrafast, sensitive, selective and robust LDTD-APCI-MS/MS method was developed for the quantification of ceritinib in human plasma. Results: Samples were protein precipitated using acetonitrile containing [13C6]-ceritinib as internal standard. The assay was validated over a concentration range from 5.00 to 1000 ng/ml. Intra- and inter-day precision and accuracy met acceptance from EMA and US FDA guidelines. The normalized recovery was 69%, whereas no carryover and matrix effects were observed. The method was applied to clinical samples and resultant data were consistent with the LC–ESI–MS/MS reference method. Conclusion: The new assay is suitable for ceritinib quantification in clinical trials, whereas the analysis time is significantly reduced to 10 s.