Comparison between ultra-performance liquid chromatography with tandem mass spectrometry and a chemiluminescence immunoassay in the determination of cyclosporin A and tacrolimus levels in whole blood

Intravenous Infusion of Fentanyl Has No Effect on Blood Concentration of Tacrolimus in Patients Receiving Hematopoietic Stem-Cell Transplantation

BACKGROUND

Both tacrolimus (TAC) and fentanyl are frequently used in patients receiving allogeneic hematopoietic stem-cell transplantation. A recently published report demonstrated that fentanyl can reduce the total body clearance of TAC; however, most patients in this study were administered concomitantly with azole antifungal agents, which are known to be strong inhibitors of CYP3A. Hence, the exact effect of fentanyl on TAC pharmacokinetics was unclear. In the current study, the authors retrospectively investigated the pharmacokinetic interaction between TAC and fentanyl in patients who were not concomitantly administered drugs that affect TAC metabolism.

METHODS

Patients with continuous infusion of TAC and fentanyl after hematopoietic stem-cell transplantation at the Tokyo Medical and Dental University between January 2014 and December 2018 were enrolled. The total body clearance of TAC was compared before and after the initiation or discontinuation of fentanyl.

RESULTS

Thirty patients (24 men and 6 women; median age, 11 years) were screened for their eligibility. Twenty-eight patients were enrolled for evaluating the effects of the fentanyl initiation on TAC pharmacokinetics; 2 patients were excluded because of the absence of data related to the TAC blood concentrations or the concomitant use of azole antifungals. Twenty patients were enrolled for investigating the effects of fentanyl discontinuation on TAC pharmacokinetics, whereas 10 patients were excluded because of the absence of data related to the blood concentration of TAC or the additional administration of azole antifungals. Furthermore, the total body clearance of TAC was not significantly affected by the initiation or discontinuation of fentanyl, although there were large interindividual variations. In addition, the results remained the same even when the analysis was performed independently for adults and children.

CONCLUSIONS

Intravenous infusion of fentanyl does not affect the pharmacokinetics of TAC.

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.

Validation of a novel UPLC-HRMS method for human whole-blood cyclosporine and comparison with a CMIA immunoassay

Therapeutic drug monitoring is an essential tool when managing the therapeutic use of immunosuppressant cyclosporine A (CsA) in cases with solid organ transplantation. In China, the concentration of CsA is primarily measured using immunoassays. However, existing literature recommends mass spectrometry as the current gold standard for the quantitation of CsA. In the present study, it was attempted to develop a novel application to determine CsA concentrations by using ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (UPLC-HRMS). This technique was then compared with a commercially available chemiluminescent microparticle immunoassay (CMIA) and it was investigated how clinical factors may contribute to quantitation differences between the two methods. An UPLC-Orbitrap-MS method was developed to determine CsA concentrations and this method was validated using guidelines put forward by the Food and Drug Administration from the US. In total, 127 blood samples were acquired from patients undergoing kidney transplantation and analyzed by UPLC-HRMS and CMIA assays. The novel method provided sensitive, accurate and precise results. The mean CsA concentration measured by CMIA was significantly higher than that measured by UPLC-HRMS (85.70±48.99 vs. 67.06±34.56 ng/ml, P<0.0001). Passing Bablok analysis yielded a slope of 1.34 (95% CI: 1.22-1.47) and an intercept of -2.54 (95% CI: -10.29-5.52). A group of samples with a higher metabolic ratio (hydroxylated CsA/CsA>1) exhibited larger discrepancies, while a group of samples taken from patients with a longer post-transplantation time (>10 years) featured narrow 95% CIs from -15.32 to 65.69%, as determined by Bland-Altman analysis. In summary, a reliable, accurate and rapid UPLC-HRMS method for CsA analysis was successfully developed. The measurement of CsA by the CMIA assay in renal transplant patients should be further evaluated with a specific focus on positive bias.

Internal standards in regulated bioanalysis: putting in place a decision-making process during method development

It is common practice to utilize an internal standard (IS) to minimize variance in bioanalytical assays employing liquid chromatography coupled to mass spectrometry. For assays to be deployed in regulated drug development studies, ensuring the IS will compensate for differences in recovery, liquid handling and ionization efficiency should be determined early in the method development process. In this perspective article, we outline key considerations when selecting an IS and propose experiments to perform within the method development phase to demonstrate suitability of the IS within the assay prior to validation. Finally, a series of case studies will be presented, which illustrate analytical challenges related to internal standardization that we have observed in our laboratory.

Impact of an immunosuppressive human pharmaceutical on the interaction of a bacterial parasite and its invertebrate host

The interaction of pollutants and pathogens may result in altered and often enhanced effects of the chemical, the biotic stressor or both. These interaction effects cannot be reliably predicted from the toxicity of the chemical or the virulence of the pathogen alone. While standardized detection methods for immunotoxic effects of chemicals exist with regard to human health, employing host-resistance assays with vertebrates, such standardized test systems are completely lacking for invertebrate species and no guidance is available on how immunotoxic effects of a chemical in invertebrates could be definitively identified. In the present study, we investigated the impact of the immunosuppressive pharmaceutical cyclosporine A (CsA) on the invertebrate host-pathogen system Daphnia magna - Pasteuria ramosa. CsA is a calcineurin-inhibitor in vertebrates and also known to have antibiotic as well as antifungal properties. Juvenile D. magna were exposed to CsA for 21 days with or without additional pathogen challenge during the first 72 h of exposure. Long-term survival of the host D. magna was synergistically impacted by co-exposure to the chemical and the pathogen, expressed e.g. in significantly enhanced hazard ratios. Additionally, enhanced virulence of the pathogen upon chemical co-exposure was expressed in an increased proportion of infected hosts and an increased speed of Pasteuria-induced host sterilization. In contrast, effects on reproduction were additive in Pasteuria-challenged, but finally non-infected D. magna. The enhancing effects of CsA occurred at and below 3 μg/L, which was in the absence of the pathogen the lowest concentration significantly impacting the standard toxicity endpoint 'reproduction' in D. magna. Hence, the present study provides evidence that a pharmaceutical intended to suppress the human immune system can also suppress disease resistance of an aquatic invertebrate organism at otherwise non-toxic concentrations. Plausible ways of direct interactions of CsA with the host's immune system are discussed, e.g. interference with phagocytosis or Toll-like receptors. Experimental verification of such a direct interference would be warranted to support the strong evidence for immunotoxic activity of CsA in invertebrates. While it remains open whether CsA concentrations in the environment are high enough to trigger adverse effects in environmental organisms, our findings highlight the need to consider immunotoxicity in an environmental risk assessment, and to develop suitable standardized methods for this purpose.

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.

A comparison of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) for the determination of the cyclosporin A concentration in whole blood from Chinese patients

Cyclosporin A (CyA) is an immunosuppressive agent widely used in clinical therapy. In the therapeutic process, the blood concentration of CyA should be monitored to avoid or prevent rejection and toxicity. The objectives of this study were to compare the correlation of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) for the determination of the CyA concentration in human blood and to provide evidence for the rational usage of EMIT in clinical practice. Blood samples collected from 132 patients undergoing a liver or kidney transplant or patients with aplastic anemia at Qilu Hospital of Shandong University were tested using the two methods. The calibration curve was linear from 25-500 ng·mL^-1 for LC-MS/MS and from 50-450 ng·mL^-1 for EMIT. The inter- and intra-day RSDs were less than 15%. The CyA blood concentration according to EMIT was 3.5 ng·mL^-1 more than that according to LC-MS/MS. The 95% confidence interval was -10.0~16.9 ng·mL^-1. The CyA blood concentration according to the two methods did not differ significantly (p > 0.05). LC-MS/MS and EMIT were suitable methods for determining the CyA blood concentration. The two methods were closely correlated (r² = 0.969), but the CyA blood concentration according to EMIT was slightly higher than that according to LC-MS/MS. The clinical significance of this finding needs to be further evaluated.

Immunosuppressive drugs in whole blood: validation of a commercially available liquid chromatography/tandem mass spectrometry kit and comparison with immunochemical assays

RATIONALE

In the determination of immunosuppressive drugs cyclosporine A (CSA), tacrolimus (TARO), sirolimus (SIRO), and everolimus (EVE) in whole blood there is an open debate about which is the best assay between immunochemistry and liquid chromatography/tandem mass spectrometry (LC/MS/MS). This work is aimed to explore this topic, focusing on the use of updated assays and the analysis of a large number of samples.

METHODS

A certified in vitro diagnostic kit coupled with a medical device LC/MS/MS was validated and applied to the analysis of 1192 blood samples of patients treated with immunosuppressive drugs. The results were compared with those obtained by immunoassays.

RESULTS

The LC/MS/MS approach was found to provide linear, stable, precise, and accurate results, with lower limits of quantification of 12.5, 1.1, 1.2, and 1.2 μg/L for CSA, TACRO, SIRO, and EVE, respectively. With this method 80 samples were analysed and reported within a single work shift. A correlation was observed between the LC/MS/MS and immunoassay data, with Spearman correlation coefficients of 0.980 (n = 260) for CSA, 0.836 for TACRO (n = 562), 0.898 for SIRO (n = 113), and 0.904 for EVE (n = 257). Passing-Bablock regression showed the presence of constant and proportional biases for most of the drugs. A Blond-Altman graph showed differences between the assays, with immunoassays generally overestimating the drugs.

CONCLUSIONS

The LC/MS/MS certified kit was validated for the detection of immunosuppressant drugs in whole blood and it provided a high-throughput method that is consistent with the requirements of clinical laboratories. The comparison of patient data between LC/MS/MS and up-dated immunoassays shows that a significant discrepancy still exists, especially for CSA and SIRO, confirming the greater specificity associated with use of the LC/MS/MS assay Copyright © 2017 John Wiley & Sons, Ltd.

Separation of cordycepin from Cordyceps militaris fermentation supernatant using preparative HPLC and evaluation of its antibacterial activity as an NAD+-dependent DNA ligase inhibitor

Cordycepin exhibits various bio-activities, including anticancer, antibacterial, antiviral and immune regulation activities, and is a significant focus of research. However, the preparation of high-purity cordycepin remains challenging. Also, the molecular target with which cordycepin interacts to cause an antibacterial effect remains unknown. In the present study, cordycepin was prepared by preparative high-performance liquid chromatography (prep-HPLC) and the purity obtained was 99.6%, indicating that this technique may be useful for the large-scale isolation of cordycepin in the future. The results of computational molecular docking analysis indicated that the interaction energy between cordycepin and NAD+-dependent DNA ligase (LigA) was lower than that between cordycepin and other common antibacterial targets. The highly pure cordycepin obtained by prep-HPLC demonstrated inhibitory activity against LigA from various bacteria in vitro. In conclusion, cordycepin may be useful as a broad-spectrum antibiotic targeting LigA in various bacteria.

Therapeutic drug monitoring of immunosuppressants by liquid chromatography-mass spectrometry

Immunosuppressant medications allow the transplantation of tens of thousands of allografts per year and consequently have great potential to decrease patient morbidity and mortality. However, some medications have great risk associated with over- and under-dosing leading to adverse effects or allograft rejection, respectively. This necessitates immunosuppressant therapeutic drug monitoring accomplished by immunoassay or liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The former's accuracy can be hindered by metabolites of immunosuppressant medications, antibodies against these medications and heterophilic antibodies. Although LC-MS/MS has superior specificity which allows it to be less susceptible to interference, this methodology lacks standardization and the necessary throughput. Recent developments in LC-MS/MS quantitation, however, include patient-friendly sample submission as dried blood spots, higher sample throughput and commercialization. Here we critically review recent LC-MS/MS publications (January 2010 to July 2015) on the quantitation of cyclosporine A, tacrolimus, sirolimus and everolimus.