UPLC-MS/MS determination of suvorexant in urine by a simplified dispersive liquid-liquid micro-extraction followed by ultrasound assisted back extraction from solidified floating organic droplets

A Simple, Sensitive, and Greener HPLC-DAD Method for the Simultaneous Analysis of Two Novel Orexin Receptor Antagonists

The orexin receptor antagonist (ORA) is one of the new psychopharmacological agents used in the treatment of insomnia. There are currently no documented greener high-performance liquid chromatography-diode array detector (HPLC-DAD) methods for the analysis of ORA antagonists, lemborexant (LMB) and suvorexant (SUV) simultaneously. Therefore, in this study, a simple, sensitive, and greener HPLC-DAD method has been developed for the simultaneous quantitative analysis of LMB and SUV in bulk and laboratory-prepared mixture. The developed method was validated for numerous validation parameters and evaluated for greenness. The C18 Waters Spherisorb CN (4.6 × 250 mm2; 5 μm) column was used for the chromatographic separation. The mobile phase composition was ethanol: 10 mM KH2PO4 buffer in a ratio of (60:40 v/v). The DAD detection was performed at 253 nm using a Waters DAD detector. The greenness was evaluated using the analytical Eco-Scale (AES), ChlorTox, and analytical GREEnness (AGREE) techniques. The calibration curves showed excellent linearity for LMB and SUV between the concentration range of 125-5000 ng/mL and 250-10,000 ng/mL, respectively. In addition, the proposed HPLC-DAD method was accurate, precise, robust, highly sensitive, and greener. AES, ChlorTox, and AGREE scales were predicted by the HPLC-DAD method to be 91, 1.14 g, and 0.79, respectively, showing an excellent greenness profile. The greener HPLC-DAD method was successfully used to analyze both medicines quantitatively in bulk and laboratory-prepared synthetic mixtures. The findings of this study indicated that the proposed HPLC-DAD method may be consistently applied to evaluate LMB and SUV in bulk and dosage forms.

Recent Advances in Dispersive Liquid-Liquid Microextraction for Pharmaceutical Analysis

Sample clean-up and pre-concentration are critical components of pharmaceutical analysis. The dispersive liquid-liquid microextraction (DLLME) technique is widely recognized as the most effective approach for enhancing overall detection sensitivity. While various DLLME modes have been advanced in pharmaceutical analysis, there need to be more discussions on pre-concentration techniques specifically developed for this field. This review presents a comprehensive overview of the different DLLME modes used in pharmaceutical analysis from 2017 to May 2023. The review covers the principles of DLLME, the factors affecting microextraction, the selected applications of different DLLME modes, and their advantages and disadvantages. Additionally, it focuses on multi-extraction strategies employed for pharmaceutical analysis.

Quantification of Suvorexant in Human Urine Using a Validated HPTLC Bioanalytical Method

Suvorexant (SUV) is a new sedative/hypnotic medicine that is recommended to treat insomnia. It is an important medicine from a forensic point of view due to its sedative/hypnotic and depressant effects. To the best of our knowledge, high-performance thin-layer chromatography (HPTLC) bioanalytical methods have not been published to measure SUV in human urine and pharmaceutical samples. Accordingly, this study was designed and validated a sensitive and rapid bioanalytical HPTLC method to determine SUV in human urine samples for the very first time. The densitometric measurement of SUV and the internal standard (IS; sildenafil) was performed on glass-coated silica gel normal-phase-60F254S TLC plates using a mixture of chloroform and methanol (97.5:2.5 v/v) as the eluent system. Both the SUV and IS were detected at a wavelength of 254 nm. Both analytes were extracted using the protein precipitation technique utilizing methanol as the solvent. For the IS and SUV, the Rf values were 0.09 and 0.45, respectively. The proposed bioanalytical method for SUV was linear in the 50-1600 ng/band range. The current bioanalytical technique was linear, precise (% RSD = 3.28-4.20), accurate (% recovery = 97.58-103.80), robust (% recovery = 95.31-102.34 and % RSD = 2.81-3.15), rapid, and sensitive (LOD = 3.73 ng/band and LOQ = 11.20 ng/band). These findings suggested that the current bioanalytical method can be regularly used to determine SUV in wide varieties of urine samples.

Quantitative determination of bromochloroacetamide in mice urine by gas chromatography combined with salting-out assisted dispersive liquid-liquid microextraction

Bromochloroacetamide (BCAcAm) is the main haloacetamide (HAcAm) detected in drinking water in different regions and exhibits strong cytotoxicity and genotoxicity. However, there is no appropriate method for detecting BCAcAm in urine or other biological samples, and thus, the internal exposure level in the population cannot be accurately assessed. In this study, a gas chromatography-electron capture detector (GC-ECD) was combined with salting-out assisted dispersive liquid-liquid microextraction (SA-DLLME) to develop a rapid and robust method for BCAcAm detection in urine of mice continuously exposed to BCAcAm. The factors influencing the pre-treatment procedure, including the type and volume of extraction and disperser solvents, extraction and standing time, and the amount of salt, were evaluated systematically. Under the optimised conditions, the analyte achieved good linearity in the spiked concentration range of 1.00-400.00 μg L^-1, and the correlation coefficient was higher than 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.17 μg L^-1 and 0.50 μg L^-1, respectively. The recoveries ranged from 84.20% to 92.17%. The detection of BCAcAm at three different calibration levels using this method afforded an intra-day precision of 1.95-4.29%, while the inter-day precision range was 5.54-9.82% (n = 6). This method has been successfully applied to monitor the concentration of BCAcAm in mouse urine in toxicity experiments and can provide technical support for assessing human internal exposure levels and health risks in later studies.

Utilization of Waste Biomaterial as an Efficient and Eco-Friendly Adsorbent for Solid-Phase Extraction of Pantoprazole Contaminants in Wastewater

The objective of this analysis is to establish the potential of biodegradable agro-industrial waste materials as biosorbents in the solid-phase extraction (SPE) technique for sample preparation. In this regard, waste coffee husk (CH) powder was collected, washed, treated chemically, characterized, and applied as an SPE adsorbent to extract pantoprazole from the wastewater samples. Sample detection was accomplished using the UPLC-MS/MS system. The positive mode of electrospray ionization was exploited for the ionization of the sample, and quantification of the target analyte was performed by the multiple reaction monitoring modes. The precursor to product ion transition of 384.02→1380.05 and 384.02→200.05 was used as qualifiers and quantifiers, respectively. Optimization of the particle size, adsorbent dose, and contact time were evaluated to select the best combination of features. The efficiency and regeneration capability of the CH were compared with respect to a commercially available silica-based C18 SPE adsorbent, and it was found that CH possessed comparable (~50%) extraction, as well as regeneration capacity (~95%). The developed biosorbent was applied in a wastewater sample spiked with the target analyte and recovery studies were performed, which found a range of 93.0 to 102.0% with a %RSD of 3.72 to 12.7%. Thus, CH can be exploited as a ‘greener’ replacement for the commercially available adsorbents for the extraction/retention of active pharmaceutical ingredients present in water/wastewater samples.

UPLC-MS/MS Based Identification and Quantification of a Novel Dual Orexin Receptor Antagonist in Plasma Samples by Validated SWGTOX Guidelines

Lemborexant (LEM) is a novel dual orexin receptor antagonist (DORA), recently approved for the treatment of insomnia. As with other DORAs, LEM has potential of abuse and therefore placed in Schedule IV class by the United States Drug Enforcement Administration (USDEA). In this study, a sensitive and accurate UPLC-MS/MS assay was developed for the quantification of LEM in human plasma sample using losartan as an internal standard (IS). The chromatographic separation was performed by using gradient elution of mobile phase, comprising of 10 mM ammonium acetate and acetonitrile with a flow rate of 0.3 mL/min. An Acquity UPLC BEH C₁₈ (1.7 μm, 2.1 × 50 mm) column was used for separation of LEM and IS by maintaining the oven temperature of 40 °C. The electrospray ionization in positive mode was used for sample ionization. The precursor to product ion transition of 411.12 > 175.09 (qualifier) and 411.1 > 287.14 (quantifier) was used for detection and quantification of LEM, respectively, in multiple reaction monitoring mode. Being a drug of abuse, the assay was validated according to "Scientific Working Group for Toxicology" (SWGTOX) guidelines, including limit of detection (LOD), limit of quantification (LOQ), precision and bias, calibration model, interferences, carry-over effects, matrix effects, and stability parameters. The LOD and LOQ of the assay were 0.35 and 1.0 ng/mL, respectively. The linear range was between 1-300 ng/mL with correlation coefficient of ≥0.995. The method was also cross validated in rat plasma samples with acceptable ranges of precision and accuracy before its application for pharmacokinetic study in rats.

Green bioanalysis: an innovative and eco-friendly approach for analyzing drugs in biological matrices

Green bioanalytical techniques aim to reduce or eliminate the hazardous waste produced by bioanalytical technologies. A well-organized and practical approach towards bioanalytical method development has an enormous contribution to the green analysis. The selection of the appropriate sample extraction process, organic mobile phase components and separation technique makes the bioanalytical method green. UHPLC-MS is the best option, whereas supercritical fluid chromatography is one of the most effective green bioanalytical procedures. Nevertheless, there remains excellent scope for further research on green bioanalytical methods. This review details the various sample preparation techniques that follow green analytical chemistry principles. Furthermore, it presents green solvents as a replacement for conventional organic solvents and highlights the strategies to convert modern analytical techniques to green methods.

Green Extraction Techniques as Advanced Sample Preparation Approaches in Biological, Food, and Environmental Matrices: A Review

Green extraction techniques (GreETs) emerged in the last decade as greener and sustainable alternatives to classical sample preparation procedures aiming to improve the selectivity and sensitivity of analytical methods, simultaneously reducing the deleterious side effects of classical extraction techniques (CETs) for both the operator and the environment. The implementation of improved processes that overcome the main constraints of classical methods in terms of efficiency and ability to minimize or eliminate the use and generation of harmful substances will promote more efficient use of energy and resources in close association with the principles supporting the concept of green chemistry. The current review aims to update the state of the art of some cutting-edge GreETs developed and implemented in recent years focusing on the improvement of the main analytical features, practical aspects, and relevant applications in the biological, food, and environmental fields. Approaches to improve and accelerate the extraction efficiency and to lower solvent consumption, including sorbent-based techniques, such as solid-phase microextraction (SPME) and fabric-phase sorbent extraction (FPSE), and solvent-based techniques (μQuEChERS; micro quick, easy, cheap, effective, rugged, and safe), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), in addition to supercritical fluid extraction (SFE) and pressurized solvent extraction (PSE), are highlighted.

Rapid analysis of triazine herbicides in fruit juices using evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets and HPLC-DAD

A rapid and convenient analytical procedure (evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets) is advanced for determining the concentrations of triazine herbicide residues (e.g. simazine and atrazine) in fruit juices via HPLC-DAD. The technique involves adding 1-dodecanol (low density) and dichloromethane (high density) to the test solution to act as the extraction and volatile solvents, respectively. Calcium oxide is added to generate heat to accelerate the evaporation of dichloromethane, whereupon the 1-dodecanol quickly disperses into small droplets to complete the microextraction process. Thus, there is no need to use a dispersive solvent and heating equipment is also not required. The floating 1-dodecanol is subsequently frozen using an ice bath to facilitate its separation from the sample. Under optimal conditions (250 μL of 1-dodecanol (extraction solvent), 150 μL of CH₂Cl₂ (volatile solvent), 1250 mg of CaO, and an extraction time of 60 s) the detection procedure is linear over the range 0.05-5 μg mL^-1 (with R > 0.99). The limits of detection (LOD) and quantification (LOQ) were determined to be 0.0022-0.0034 μg mL^-1 and 0.0073-0.0113 μg mL^-1, respectively. The recovery of simazine and atrazine in three fruit juices ranged between 78.5% and 96.4% with a relative standard deviation <8.2%. Therefore, the proposed approach can be effectively adopted to analyze the triazine herbicide content in fruit juices. The method has been proved to be simple, reliable, and remarkably efficient.

Current development of bioanalytical sample preparation techniques in pharmaceuticals

Sample preparation is considered as the bottleneck step in bioanalysis because each biological matrix has its own unique challenges and complexity. Competent sample preparation to extract the desired analytes and remove redundant components is a crucial step in each bioanalytical approach. The matrix effect is a key hurdle in bioanalytical sample preparation, which has gained extensive consideration. Novel sample preparation techniques have advantages over classical techniques in terms of accuracy, automation, ease of sample preparation, storage, and shipment and have become increasingly popular over the past decade. Our objective is to provide a broad outline of current developments in various bioanalytical sample preparation techniques in chromatographic and spectroscopic examinations. In addition, how these techniques have gained considerable attention over the past decade in bioanalytical research is mentioned with preferred examples. Modern trends in bioanalytical sample preparation techniques, including sorbent-based microextraction techniques, are primarily emphasized.

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Bioanalytical sampling techniques are described with suitable applications in pharmaceuticals.

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The pros and cons of each bioanalytical sampling techniques are described.

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Relevant biological matrices are outlined.

UPLC-MS/MS assay for the simultaneous determination of pyrotinib and its oxidative metabolite in rat plasma: Application to a pharmacokinetic study

Pyrotinib is an irreversible EGFR/HER2 inhibitor that has been approved for the treatment of breast cancer. The aim of this work was to establish a quantification method for the simultaneous determination of pyrotinib and its metabolite pyrotinib-lactam in rat plasma using UPLC-MS/MS. After simple protein precipitation with acetonitrile, the analytes and internal standard (neratinib) were separated on an ACQUITY BEH C₁₈ column (2.1 × 50 mm, 1.7 μm) using a mobile phase of water containing 0.1% formic acid and acetonitrile. The detection was performed using selected reaction monitoring mode with precursor-to-product ion transitions at m/z 583.2 > 138.1 for pyrotinib, m/z 597.2 > 152.1 for pyrotinib-lactam, and m/z 557.2 > 112.1 for internal standard. The assay exhibited excellent linearity in the concentration range of 0.5-1000 ng/mL for pyrotinib and pyrotinib-lactam. The assay met the criteria of the United States Food and Drug Administration-validated bioanalytical methods and was successfully applied to a pharmacokinetic study of pyrotinib and its metabolite for the first time. Our results demonstrated that pyrotinib rapidly converted into pyrotinib-lactam, whose in vivo exposure was 21% that of pyrotinib.

Recent developments in sample preparation techniques combined with high-performance liquid chromatography: A critical review

This review article compares and contrasts sample preparation techniques coupled with high-performance liquid chromatography (HPLC) and describes applications developed in biomedical, forensics, and environmental/industrial hygiene in the last two decades. The proper sample preparation technique can offer valued data for a targeted application when coupled to HPLC and a suitable detector. Improvements in sample preparation techniques in the last two decades have resulted in efficient extraction, cleanup, and preconcentration in a single step, thus providing a pathway to tackle complex matrix applications. Applications such as biological therapeutics, proteomics, lipidomics, metabolomics, environmental/industrial hygiene, forensics, glycan cleanup, etc., have been significantly enhanced due to improved sample preparation techniques. This review looks at the early sample preparation techniques. Further, it describes eight sample preparation technique coupled to HPLC that has gained prominence in the last two decades. They are (1) solid-phase extraction (SPE), (2) liquid-liquid extraction (LLE), (3) gel permeation chromatography (GPC), (4) Quick Easy Cheap Effective Rugged, Safe (QuEChERS), (5) solid-phase microextraction (SPME), (6) ultrasonic-assisted solvent extraction (UASE), and (7) microwave-assisted solvent extraction (MWASE). SPE, LLE, GPC, QuEChERS, and SPME can be used offline and online with HPLC. UASE and MWASE can be used offline with HPLC but have also been combined with the online automated techniques of SPE, LLE, GPC, or QuEChERS for targeted analysis. Three application areas of biomedical, forensics, and environmental/industrial hygiene are reviewed for the eight sample preparation techniques. Three hundred and twenty references on the eight sample preparation techniques published over the last two decades (2001-2021) are provided. Other older references were included to illustrate the historical development of sample preparation techniques.

An Ultraperformance Liquid Chromatography Tandem-Mass Spectrometry Method for Determination of Multiclass Pharmaceuticals in Water Sample by Dispersive Liquid-Liquid Microextraction Combined with Ultrasound Assisted Reverse Extraction from Solidified Floating Organic Droplets

A novel, simple, and reliable ultraperformance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS ) assay based on dispersive liquid-liquid microextraction followed by ultrasound-assisted reverse extraction from solidified floating organic droplets was established for determination of multiclass pharmaceuticals in the water sample. Six commonly used drugs of various therapeutic classes: ibuprofen, ketorolac, lamotrigine, propranolol, pantoprazole, and losartan were extracted from water samples by using 50 μL 1-undecanol as extracting solvent and 400 μL acetonitrile as dispersive solvent. After collecting the floating organic droplets by cold centrifugation, an ultrasound-assisted back extraction procedure was performed to make the sample compatible for UPLC-MS/MS analysis. Acquity BEH C₁₈ column (2.1 × 100; 1.7 μm) was used for separation of target analytes that were eluted by a gradient mobile phase composition of 15 mM ammonium acetate and acetonitrile at a flow rate of 0.25 mL/min. The sample ionization was performed by using electrospray ionization in positive mode, and multiple reaction monitoring was used for quantification of target analytes. After optimizing the assay conditions, all calibration curves were found to be linear with limit of detection and limit of quantification were ranged in between 0.06-0.15 and 0.16-0.41 ng/mL, respectively. The enrichment factor was found to be 172-192-fold and the relative recovery was ranged between 93.1 and 109.4% between target analytes. These satisfactory results confirmed that the proposed method is specific and reliable for application of trace analysis of target analytes in waste water samples.

Development and validation of a UPLC-MS/MS method for quantification of C-005, a novel third-generation EGFR TKI, and its major metabolite in plasma: Application to its first-in-patient study

C-005 is a novel third-generation EGFR tyrosine kinase inhibitor for the treatment of non-small cell lung cancer (NSCLC). To support its clinical trial, we developed a rapid and sensitive bioanalytical method based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technique for the quantification of C-005 and its major metabolite in NSCLC patients following international bioanalytical guidelines. After a simple and quick protein precipitation step, the supernatant was injected to a Waters Acquity BEH C₁₈ column (2.1 × 50 mm i.d., 1.7 mm), and the column was eluted with a gradient of buffer A (5 mM ammonium acetate and 0.1% formic acid in water) and buffer B (formic acid-acetonitrile (1:1000, v/v)). The eluates were subsequently detected by an AB QTRAP 5500 mass spectrometer with electrospray ionization using multiple-reaction monitoring mode. The method showed good linearity from 2.00 to 1000 ng/mL for C-005 and 1.00 to 500 ng/mL for M1. In conclusion, the validation results demonstrated the robustness of the method and its well-poised to support the first-in-patient study of C-005 in NSCLC patients.

A validated LC-MS/MS method for the determination of RAF inhibitor LXH254: Application to pharmacokinetic study in rat

In this study, a simple and sensitive UHPLC-ESI-MS/MS method was established for the determination of LXH254 in rat plasma. The developed method was validated according to the Food and Drug administration guidelines. After extraction using ethyl acetate, the sample was separated on an ACQUITY BEH C₁₈ column. The mobile phase consisted of 2 mM ammonium acetate containing 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. The flow rate was 0.3 mL/min. A TSQ triple quadrupole mass spectrometer operated in positive-ion mode was used for mass detection, with multiple reaction monitoring transitions of m/z 503.3 > 459.1 and m/z 435.3 > 367.1 for LXH254 and olaparib (internal standard), respectively. An excellent linearity was achieved in the concentration range of 0.1-1000 ng/mL, with correlation coefficient >0.998. The mean recovery was more than 78.55%. Inter- and intra-day precision (percentage of relative standard deviation) did not exceed 12.87%, and accuracy was in the range of -2.50 to 13.50%. LXH254 was demonstrated to be stable under the tested storage conditions. The validated UHPLC-MS/MS method was further applied to the pharmacokinetic study of LXH254 in rat plasma after oral (2, 5, and 15 mg/kg) and intravenous (2 mg/kg) administrations. The pharmacokinetic study revealed that LXH254 showed low clearance, moderate bioavailability (~30%), and linear pharmacokinetic profile over the oral dose range of 2-15 mg/kg. To the best of our knowledge, this is the first report on the method development and validation of the determination of LXH254 and its application to pharmacokinetic study.

Bioanalysis of pharmaceuticals using liquid-phase microextraction combined with liquid chromatography-mass spectrometry

In this paper, we review recent research articles on liquid-phase microextraction of drug substances from biological fluids, such as plasma, serum, urine, and saliva. We focus on papers where liquid-phase microextraction is combined with liquid chromatography coupled with mass spectrometry (LC-MS), published in the period 2019-2020. First, we discuss different configurations of liquid-phase microextraction, including dispersive liquid-liquid microextraction (DLLME), dispersive liquid-liquid microextraction based on solidified floating organic droplet (DLLME-SFO), single-drop microextraction (SDME), hollow-fibre liquid-phase microextraction (HF-LPME), solvent bar microextraction (SBME), and electromembrane extraction (EME). Second, we discuss new types of solvents used in liquid-phase microextraction, including ionic liquids, deep eutectic solvents, and nanostructured supramolecular solvents. Especially, we focus on the potential for implementation in routine laboratories, which we consider as the next step for liquid-phase microextraction.

CYP450-Mediated metabolism of suvorexant and investigation of metabolites in forensic case specimens

Suvorexant (Belsomra®) is a sedative hypnotic that was approved for use in 2015. It has a novel mechanism of action and was the first dual orexin receptor antagonist (DORA) to be approved for the treatment of sleep disorders. Sedative hypnotics often feature prominently in forensic investigations such as impaired driving and drug-facilitated sexual assault (DFSA) cases. As such, suvorexant is a drug of interest and its identification in forensic toxicology investigations is of significance. However, limited studies have been published to date and the disposition or importance of its metabolites has been largely uninvestigated. In this report, we investigate the enzymes responsible for metabolism and explore the prevalence of metabolites in blood from a series of thirteen forensic investigations. Recombinant cytochrome P450 enzymes (rCYPs) were used to generate phase I metabolites for suvorexant in vitro, and metabolites were identified using liquid chromatography-quadrupole/time-of-flight-mass spectrometry (LC-Q/TOF-MS). Four rCYP isoenzymes (3A4, 2C19, 2D6, and 2C9) were found to contribute to suvorexant metabolism. The only metabolite identified in blood or plasma arose from hydroxylation of the benzyl triazole moiety (M9). This metabolite was identified in seventeen blood and plasma specimens from twelve medicolegal death investigations and one impaired driving investigation. In the absence of a commercially available reference material, the metabolite was confirmed using rCYP-generated in vitro controls using high resolution mass spectrometry.

Identification of Suvorexant in Blood Using LC–MS-MS: Important Considerations for Matrix Effects and Quantitative Interferences in Targeted Assays

Suvorexant (Belsomra®) is a novel dual orexin receptor antagonist used for the treatment of insomnia. The prevalence of suvorexant in forensic samples is relatively unknown, which demonstrates the need for robust analytical assays for the detection of this sedative hypnotic in forensic toxicology laboratories. In this study, suvorexant was isolated from whole blood using a simple acidic/neutral liquid–liquid extraction followed by analysis by liquid chromatography tandem mass spectrometry (LC–MS/MS). Matrix effects were evaluated qualitatively and quantitatively using various extraction solvents, proprietary lipid clean-up devices and source conditions. The method was validated in terms of limit of detection, limit of quantitation, precision, bias, calibration model, carryover, matrix effects and drug interferences. Electrospray is a competitive ionization process whereby compounds in the droplet compete for a limited number of charged sites at the surface. As such, it is capacity-limited, and LC–MS-based techniques must be carefully evaluated to ensure that matrix effects or coeluting drugs do not impact quantitative assay performance. In this report, we describe efforts to ameliorate such effects in the absence of an isotopically labeled internal standard. Matrix effects are highly variable and heavily dependent on the physico-chemical properties of the substance. Although there is no universal solution to their resolution, conditions at the electrospray interface can mitigate these issues. Using this approach, the LC–MS/MS assay was fully validated and limits of detection and quantitation of 0.1 and 0.5 ng/mL suvorexant were achieved in blood.

Simultaneous determination of evobrutinib and its metabolite evobrutinib-diol in dog plasma by liquid chromatography combined with electrospray ionization tandem mass spectrometry

A rapid and sensitive liquid chromatography hyphenated with electrospray ionization tandem mass spectrometric method (LC-ESI-MS/MS) was developed and validated for simultaneous determination of evobrutinib and evobrutinib-diol in dog plasma. The plasma sample was processed using acetonitrile and chromatographic separation was carried out on a Waters Acquity BEH C₁₈ column (50 × 2.1 mm, 1.7 μm). The mobile phase was composed of 0.1% formic acid and acetonitrile, with an optimized gradient elution at a flow rate of 0.4 mL/min. Detection was accomplished in selective reaction monitoring mode via electrospray ionization interface operated in positive ion mode. The precursor-to-product transitions for quantification were m/z 430.2 → 98.1 for evobrutinib, m/z 464.2 → 98.1 for evobrutinib-diol and m/z 441.2 → 138.1 for ibrutinib (internal standard). The developed assay was linear over the tested concentration ranges with correlation coefficient >0.995. The LLOQ was 0.1 ng/mL for both analytes. The inter- and intra-day precisions were <9.65% and the accuracy ranged from -3.94 to 6.37%. The extraction recovery was >85.41% and no significant matrix effect was observed. The developed assay was successfully applied to the pharmacokinetic study of evobrutinib and evobrutinib-diol in dogs after oral administration of evobrutinib at a single dose of 5 mg/kg.