Analytical Chemistry, Drug Discovery, Pharmaceutical Science, General Pharmacology, Toxicology and Pharmaceutics
8
Scopus Publications
Scopus Publications
Development of a Robust Platform for Infrared Ion Spectroscopy: A New Addition to the Analytical Toolkit for Enhanced Metabolite Structure Elucidation Teun van Wieringen, Arnaud Lubin, Rianne van Outersterp, Jonathan Martens, Eric van Beelen, Jos Oomens, Filip Cuyckens, Giel Berden Analytical Chemistry, 2025 Metabolite identification is essential in drug metabolism and pharmacokinetics (DMPK) studies and plays a pivotal role throughout the drug development process, from informing drug design to evaluating safety and efficacy. Mass spectrometry (MS) is the analytical technique of choice for characterizing metabolites due to its selectivity and sensitivity, particularly when paired with chromatographic methods. However, MS encounters challenges in structural characterization. This study employs infrared ion spectroscopy (IRIS) to differentiate isomeric compounds and demonstrates the robustness of a newly developed IRIS platform. We showcase applications in metabolite identification by determining the site of glucuronidation and phase I oxidation in selected drug molecules. Employing density functional theory for spectral prediction, IRIS decreases reliance on reference standards and alleviates the time-consuming purification processes typically associated with metabolite analysis. The newly developed platform integrates a high-power, high-repetition-rate infrared laser and ion trap MS. This setup is very robust, as evidenced by the highly reproducible IRIS spectra recorded over a one-year period without any instrument readjustment or recalibration. Moreover, the high power and high repetition rate of the laser provide a large dynamic range that is necessary to resolve all spectral features. These results leverage IRIS toward a transformative tool in analytical chemistry, with potential applications expanding across various fields, such as impurity analysis and forensics. The introduction of a compact IRIS setup in an industrial setting not only confirms its practical applicability but also emphasizes its potential for integration into routine analytical workflows.
Identification of Drug Metabolites with Infrared Ion Spectroscopy – Application to Midazolam in vitro Metabolism** Rianne E. van Outersterp, Jonathan Martens, Giel Berden, Arnaud Lubin, Filip Cuyckens, Jos Oomens Chemistry Methods, 2023 The identification of biotransformation products of drug compounds is a crucial step in drug development. Over the last decades, liquid chromatography‐mass spectrometry (LC‐MS) has become the method of choice for metabolite profiling because of its high sensitivity and selectivity. However, determining the full molecular structure of the detected metabolites, including the exact biotransformation site, remains challenging on the basis of MS alone. Here we explore infrared ion spectroscopy (IRIS) as a novel MS‐based method for the elucidation of metabolic pathways in drug metabolism research. Using the drug midazolam as an example, we identify several biotransformation products directly from an in vitro drug incubation sample. We show that IR spectra of the aglycone MS/MS fragment ions of glucuronide metabolites establish a direct link between detected phase I and phase II metabolites. Moreover, using quantum‐chemically computed IR spectra of candidate structures, we are able to assign the exact sites of biotransformation in absence of reference standards. Additionally, we demonstrate the utility of IRIS for structural elucidation by identifying several ring‐opened midazolam derivatives formed in an acidic environment.
Strategies and analytical workflows to extend the dynamic range in quantitative LC-MS/MS analysis Emmanuel Njumbe Ediage, Tania Aerts, Arnaud Lubin, Filip Cuyckens, Lieve Dillen, Tom Verhaeghe Bioanalysis, 2019 Aim: To evaluate alternative analytical strategies to extend the dynamic range in quantitative LC-MS/MS. Methodology & results: Two approaches based on prior or no prior knowledge of expected exposure levels were evaluated. These approaches make use of two analytical strategies, which include the use of more than one injection volume or dilution of sample extract with solvents or solvent mixtures. A total of 16 compounds with varying logP values were classified into polar and nonpolar groups and used in this evaluation. From the two analytical strategies, three workflows were derived. Conclusion: All three workflows were successfully evaluated and resulted in good accuracy (80-120%) for all the compound groups.
Atmospheric Pressure Ionization Using a High Voltage Target Compared to Electrospray Ionization Arnaud Lubin, Steve Bajic, Deirdre Cabooter, Patrick Augustijns, Filip Cuyckens Journal of the American Society for Mass Spectrometry, 2017 A new atmospheric pressure ionization (API) source, viz. UniSpray, was evaluated for mass spectrometry (MS) analysis of pharmaceutical compounds by head-to-head comparison with electrospray ionization (ESI) on the same high-resolution MS system. The atmospheric pressure ionization source is composed of a grounded nebulizer spraying onto a high voltage, cylindrical stainless steel target. Molecules are ionized in a similar fashion to electrospray ionization, predominantly producing protonated or deprotonated species. Adduct formation (e.g., proton and sodium adducts) and in-source fragmentation is shown to be almost identical between the two sources. The performance of the new API source was compared with electrospray by infusion of a mix of 22 pharmaceutical compounds with a wide variety of functional groups and physico-chemical properties (molecular weight, logP, and pKa) in more than 100 different conditions (mobile phase strength, solvents, pH, and flow rate). The new API source shows an intensity gain of a factor 2.2 compared with ESI considering all conditions on all compounds tested. Finally, some hypotheses on the ionization mechanism, similarities, and differences with ESI, are discussed. Graphical Abstract ᅟ.
