Resolving the microcosmos of complex samples: UPLC/travelling wave ion mobility separation high resolution mass spectrometry for the analysis of in vivo drug metabolism studies

Potential of measured relative shifts in collision cross section values for biotransformation studies

Ion mobility spectrometry-mass spectrometry (IMS-MS) separates gas phase ions due to differences in drift time from which reproducible and analyte-specific collision cross section (CCS) values can be derived. Internally conducted in vitro and in vivo metabolism (biotransformation) studies indicated repetitive shifts in measured CCS values (CCSmeas) between parent drugs and their metabolites. Hence, the purpose of the present article was (i) to investigate if such relative shifts in CCSmeas were biotransformation-specific and (ii) to highlight their potential benefits for biotransformation studies. First, mean CCSmeas values of 165 compounds were determined (up to n = 3) using a travelling wave IMS-MS device with nitrogen as drift gas (TWCCSN2, meas). Further comparison with their predicted values (TWCCSN2, pred, Waters CCSonDemand) resulted in a mean absolute error of 5.1%. Second, a reduced data set (n = 139) was utilized to create compound pairs (n = 86) covering eight common types of phase I and II biotransformations. Constant, discriminative, and almost non-overlapping relative shifts in mean TWCCSN2, meas were obtained for demethylation (- 6.5 ± 2.1 Å2), oxygenation (hydroxylation + 3.8 ± 1.4 Å2, N-oxidation + 3.4 ± 3.3 Å2), acetylation (+ 13.5 ± 1.9 Å2), sulfation (+ 17.9 ± 4.4 Å2), glucuronidation (N-linked: + 41.7 ± 7.5 Å2, O-linked: + 38.1 ± 8.9 Å2), and glutathione conjugation (+ 49.2 ± 13.2 Å2). Consequently, we propose to consider such relative shifts in TWCCSN2, meas (rather than absolute values) as well for metabolite assignment/confirmation complementing the conventional approach to associate changes in mass-to-charge (m/z) values between a parent drug and its metabolite(s). Moreover, the comparison of relative shifts in TWCCSN2, meas significantly simplifies the mapping of metabolites into metabolic pathways as demonstrated.

Untargeted Metabolomic Analysis Combined With Multivariate Statistics Reveal Distinct Metabolic Changes in GPR40 Agonist-Treated Animals Related to Bile Acid Metabolism

Metabolomics has been increasingly applied to biomarker discovery, as untargeted metabolic profiling represents a powerful exploratory tool for identifying causal links between biomarkers and disease phenotypes. In the present work, we used untargeted metabolomics to investigate plasma specimens of rats, dogs, and mice treated with small-molecule drugs designed for improved glycemic control of type 2 diabetes mellitus patients via activation of GPR40. The in vivo pharmacology of GPR40 is not yet fully understood. Compounds targeting this receptor have been found to induce drug-induced liver injury (DILI). Metabolomic analysis facilitating an integrated UPLC-TWIMS-HRMS platform was used to detect metabolic differences between treated and non-treated animals within two 4-week toxicity studies in rat and dog, and one 2-week toxicity study in mouse. Multivariate statistics of untargeted metabolomics data subsequently revealed the presence of several significantly upregulated endogenous compounds in the treated animals whose plasma level is known to be affected during DILI. A specific bile acid metabolite useful as endogenous probe for drug-drug interaction studies was identified (chenodeoxycholic acid-24 glucuronide), as well as a metabolic precursor indicative of acidic bile acid biosynthesis (7α-hydroxy-3-oxo-4-cholestenoic acid). These results correlate with typical liver toxicity parameters on the individual level.

Metabolite identification using an ion mobility enhanced data-independent acquisition strategy and automated data processing

RATIONALE

Liquid chromatography/mass spectrometry is an essential tool for efficient and reliable quantitative and qualitative analysis and underpins much of contemporary drug metabolism and pharmacokinetics. Data-independent acquisition methods such as MS^E have reduced the potential to miss metabolites, but do not formally generate quadrupole-resolved product ion spectra. The addition of ion mobility separation to these approaches, for example, in High-Definition MS^E (HDMS^E ) has the potential to reduce the time needed to set up an experiment and maximize the chance that all metabolites present can be resolved and characterized. We compared High-Definition Data-Dependent Acquisition (HD-DDA), MS^E and HDMS^E approaches using automated software processing with Mass-MetaSite and WebMetabase.

METHODS

Metabolite identification was performed on incubations of glucagon-like peptide-1 (7-37) (GLP-1) and verapamil hydrochloride. The HD-DDA, MS^E and HDMS^E experiments were conducted on a Waters ACQUITY UPLC I-Class LC system with a VION IMS quadrupole time-of-flight (QTOF) mass spectrometer operating under UNIFI control. All acquired data were processed using MassMetaSite able to read data from UNIFI 1.9.4. WebMetabase was used to review the detected chromatographic peaks and the spectral data interpretations.

RESULTS

A comparison of outcomes obtained for MS^E and HDMS^E data demonstrated that the same structures were proposed for metabolites of both verapamil and GLP-1. The ratio of structurally matched to mismatched product ions found by MassMetaSite was slightly greater for HDMS^E than for MS^E , and HD-DDA, thus improving confidence in the structures proposed through the addition of ion mobility based data acquisitions_. CONCLUSIONS: HDMS^E data acquisition is an effective approach for the elucidation of metabolite structures for both small molecules and peptides, with excellent accuracy and quality, requiring minimal tailoring for the compound under investigation.

Quantitative analysis of flavonols, flavonol glycoside and homoisoflavonoids in Polygonatum verticillatum using UHPLC-DAD-QTOF-IMS and evaluation of their antioxidant potential

INTRODUCTION

Polygonatum is widely used as a part of food in different regions of the world which covers five main categories such as drinks, vegetables, snacks, staple and seasoning foods. Presently, no analytical method is available for the quality control of Polygonatum.

OBJECTIVE

Development and validation of a method using ultrahigh-performance liquid chromatography diode array detector quadrupole time-of-flight (UHPLC-DAD/QTOF) technique for the estimation of six compounds including a flavonol glycoside [rutin (1)], two flavonols [quercetin (2) and kaempherol (3)] and three homoisoflavonoids [5,7-dihydroxy-3-(2-hydroxy-4-methoxybenzyl)-chroman-4-one (4), 5,7-dihydroxy-3-(2-hydroxy-4-methoxybenzyl)-8-methylchroman-4-one (5) and 5,7-dihydroxy-3-(4-methoxybenzyl)-8-methylchroman-4-one (6)]. In addition, screening of extract, fractions and compounds of P. verticillatum for antioxidant activity was also determined.

METHODOLOGY

The separation was achieved on C-18 column using acetonitrile and water containing 0.1% formic acid. The method was validated as per ICH (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use) guidelines. The validated method was applied for the simultaneous identification and quantification of compounds 1-6 in extract (E) and fractions (F1-F4) of P. verticillatum. Furthermore, antioxidant potential of E, F1 and F2 and compounds was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay.

RESULTS

The method was within the linear range (r² ) of 0.982 to 0.999, precise (intra- and inter-day percentage relative standard deviations < 2.72 and 2.26) and accurate with recoveries (89.1-98.3%). The limit of detection and limit of quantification were in the ranges 0.02-0.16 and 0.06-0.48 ng/mL, respectively. Compounds 1-6 were quantified in all the samples. Compounds 1, 2 and 5 showed higher activity with half maximal inhibitory concentration (IC₅₀ ) values 0.41, 0.39, 0.72 at 10, 20 and 30 μg/mL, respectively.

CONCLUSION

Developed method will be helpful to assess the quality of P. verticillatum raw material and their derived products.

Mass spectrometry in drug metabolism and pharmacokinetics: Current trends and future perspectives

Drug Metabolism and Pharmacokinetics (DMPK) is a core scientific discipline within drug discovery and development as well as post-marketing. It helps to design and select the most promising drug candidate and obtain advanced insights on the processes that control absorption, distribution, metabolism and excretion (ADME) of the final drug candidate. Mass spectrometry is one of the key technologies applied in DMPK. Therefore, the continuous advances made in the field of mass spectrometry also directly impact the way in which we investigate the ADME properties of a compound, providing us with new tools to gather more information or improve our efficiency. An overview will be given of some important current trends and future perspectives in the field.

Ion mobility spectrometry combined with ultra performance liquid chromatography/mass spectrometry for metabolic phenotyping of urine: Effects of column length, gradient duration and ion mobility spectrometry on metabolite detection

The need for rapid and efficient high throughput metabolic phenotyping (metabotyping) in metabolomic/metabonomic studies often requires compromises to be made between analytical speed and metabolome coverage. Here the effect of column length (150, 75 and 30 mm) and gradient duration (15, 7.5 and 3 min respectively) on the number of features detected when untargeted metabolic profiling of human urine using reversed-phase gradient ultra performance chromatography with, and without, ion mobility spectrometry, has been examined. As would be expected, reducing column length from 150 to 30 mm, and gradient duration, from 15 to 3 min, resulted in a reduction in peak capacity from 311 to 63 and a similar reduction in the number of features detected from over ca. 16,000 to ca. 6500. Under the same chromatographic conditions employing UPLC/IMS/MS to provide an additional orthogonal separation resulted in an increase in the number of MS features detected to nearly 20,000 and ca. 7500 for the 150 mm and the 30 mm columns respectively. Based on this limited study the potential of LC/IMS/MS as a tool for improving throughput and increasing metabolome coverage clearly merits further in depth study.

•

Ion mobility spectrometry (IMS) significantly increased the number of analytes detected during the LC-MS of urine.

•

Nearly ca. 20,000 features were seen for urine using LC-IMS-MS in a 15 min analysis compared to ca. 16,000 by LC-MS alone.

•

In a 3 min analysis using a 30 mm column nearly 7600 features were detected with combined IMS and MS.

•

For high throughput analysis a 75 mm column and a 3 min analysis was a good compromise between speed and features detected.

•

The use of IMS also improved the quality of the mass spectra obtained.

In vivo drug metabolite identification in preclinical ADME studies by means of UPLC/TWIMS/high resolution-QTOF MS(E) and control comparison: cost and benefit of vehicle-dosed control samples

1. Liquid chromatography (LC)-high resolution mass spectrometry (HRMS) techniques proved to be well suited for the identification of predicted and unexpected drug metabolites in complex biological matrices. 2. To efficiently discriminate between drug-related and endogenous matrix compounds, however, sophisticated postacquisition data mining tools, such as control comparison techniques are needed. For preclinical absorption, distribution, metabolism and excretion (ADME) studies that usually lack a placebo-dosed control group, the question arises how high-quality control data can be yielded using only a minimum number of control animals. 3. In the present study, the combination of LC-traveling wave ion mobility separation (TWIMS)-HRMS(E) and multivariate data analysis was used to study the polymer patterns of the frequently used formulation constituents polyethylene glycol 400 and polysorbate 80 in rat plasma and urine after oral and intravenous administration, respectively. 4. Complex peak patterns of both constituents were identified underlining the general importance of a vehicle-dosed control group in ADME studies for control comparison. Furthermore, the detailed analysis of administration route, blood sampling time and gender influences on both vehicle peak pattern as well as endogenous matrix background revealed that high-quality control data is obtained when (i) control animals receive an intravenous dose of the vehicle, (ii) the blood sampling time point is the same for analyte and control sample and (iii) analyte and control samples of the same gender are compared.

Electrospray Quadrupole Travelling Wave Ion Mobility Time-of-Flight Mass Spectrometry for the Detection of Plasma Metabolome Changes Caused by Xanthohumol in Obese Zucker (fa/fa) Rats

This study reports on the use of traveling wave ion mobility quadrupole time-of-flight (ToF) mass spectrometry for plasma metabolomics. Plasma metabolite profiles of obese Zucker fa/fa rats were obtained after the administration of different oral doses of Xanthohumol; a hop-derived dietary supplement. Liquid chromatography coupled data independent tandem mass spectrometry (LC-MSE) and LC-ion mobility spectrometry (IMS)-MSE acquisitions were conducted in both positive and negative modes using a Synapt G2 High Definition Mass Spectrometry (HDMS) instrument. This method provides identification of metabolite classes in rat plasma using parallel alternating low energy and high energy collision spectral acquisition modes. Data sets were analyzed using pattern recognition methods. Statistically significant (p < 0.05 and fold change (FC) threshold > 1.5) features were selected to identify the up-/down-regulated metabolite classes. Ion mobility data visualized using drift scope software provided a graphical read-out of differences in metabolite classes.