Differential Mobility Spectrometry Coupled with Multiple Ion Monitoring in Regulated LC-MS/MS Bioanalysis of a Therapeutic Cyclic Peptide in Human Plasma

Overcoming the challenge of potent endogenous interferences in limaprost quantification: An innovative methodology combining differential mobility spectrometry with LC-MS/MS for ultra-high sensitivity, selectivity and significantly enhanced throughput

Limaprost, an orally administered analogue of prostaglandin E1, possesses potent vasodilatory, antiplatelet, and cytoprotective properties. Due to its extremely low therapeutic doses and exceedingly low plasma concentrations, the pharmacokinetic and bioequivalence studies of limaprost necessitate a highly sensitive quantitative method with a sub-pg/mL level of lower limit of quantification. Moreover, the intensity of endogenous interferences can even exceed the maximum concentration level of limaprost in human plasma, presenting further challenge to the quantification of limaprost. As a result, existing methods have not yet met the necessary level of sensitivity, selectivity, and throughput needed for the quantitative analysis of limaprost in pharmacokinetic and bioequivalence investigations. This study presents a new methodology that combines differential mobility spectrometry (DMS) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and utilizes a distinctive strategy to achieve more accurate DMS conditions. This integration yields a method that is currently the most sensitive and features the shortest analytical time, making it the sole technique capable of meeting the requirements for limaprost pharmacokinetic and bioequivalence investigations. This method demonstrates robustness and is successfully employed in a pharmacokinetic investigation of limaprost in human subjects, underscoring that the combination of DMS with LC-MS/MS serves as an efficacious strategy for overcoming the challenges inherent in analyzing biological samples afflicted by multiple interferences.

Direct infusion-multiple reaction monitoring cubed (DI-MRM3) enables widely targeted bi-omics of Colla Corii Asini (Chinese name: Ejiao)

Food authenticity is extremely important and widely targeted bi-omics is a promising pipeline attributing to incorporating metabolomics and peptidomics. Colla Corii Asini (CCA, Ejiao) is one of the most popular tonic edible materials, with counterfeit and adulterated products being widespread. An attempt was devoted to develop a high-throughput and reliable DI-MRM3 program facilitating widely targeted bi-omics of CCA. Firstly, predictive MRM program captured metabolites and peptides in trypsin-digestive gelatins. After data alignment and structure annotation, primary parameters such as Q1 → Q3 → QLIT, CE, and EE were optimized for all 17 metabolites and 34 peptides by online ER-MS. Though a single run merely consumed 6.5 min, great selectivity was reached for each analyte. Statistical results showed that nine peptides contributed to distinguish CCA from other gelatins. After cross-validation with LC-MRM, DI-MRM3 was justified to be reproducible and high-throughput for widely targeted bi-omics of CCA, suggesting a meaningful tool for food authenticity.

Application of in-source fragmentation to the identification of perfluoropentanoic acid and perfluorobutanoic acid in environmental matrices and human serum by isotope dilution liquid chromatography coupled with tandem mass spectrometry

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is the most common analytical technique for per- and polyfluoroalkyl substances (PFASs) research and monitoring. The PFAS identification requires a minimum of two multiple reaction monitoring (MRM) transition ions as quantifier transition ion and qualifier transition ion, respectively. The second transition ion abundance for perfluoropentanoic acid (PFPeA) and perfluobutanoic acid (PFBA) is too low for practical use. A method using the in-source fragment ions as the precursor ion for MRM or pseudo-MRM has been developed and evaluated for PFPeA and PFBA identification in various environmental abiotic and biotic samples including water, soil, sediment, WWTP sludge, fruits, vegetables, egg, macrophytes, fish, dolphin liver and human serum. The PFPeA qualifier MRM transition ion (m/z = 219 > 69) has been successfully applied in all the matrices with spike recoveries (90-125%), signal to noise ratios (>10) and transition ions ratio variation (80-120%). The PFBA qualifier pseudo-MRM transition ion (m/z = 169 > 169) works well in all the matrices except dolphin liver sample. The interpretation of pseudo-MRM results should be with cautions due to lower specificity compared to MRM. In addition, this project indicated under typical chromatographic conditions the MRM isobaric interference does happen frequently to PFPeA quantifier transition ion (m/z = 263 > 219) in serum and fish composite samples, and to PFBA quantifier transition ion (m/z = 213 > 169) in macrophytes, fish composite and dolphin liver samples.

Differential Mobility Spectrometry-Tandem Mass Spectrometry with Multiple Ion Monitoring Coupled with in Source-Collision Induced Dissociation: A New Strategy for the Quantitative Analysis of Pharmaceutical Polymer Excipients in Rat Plasma

Polylactic acids (PLAs) are synthetic polymers composed of repeating lactic acid subunits. For their good biocompatibility, PLAs have been approved and widely applied as pharmaceutical excipients and scaffold materials. Liquid chromatography-tandem mass spectrometry is a powerful analytical tool not only for pharmaceutical ingredients but also for pharmaceutical excipients. However, the characterization of PLAs presents particular problems for mass spectrometry techniques. In addition to their high molecular weights and wide polydispersity, multiple charging and various adductions are intrinsic features of electrospray ionization. In the present study, a strategy combining of differential mobility spectrometry (DMS), multiple ion monitoring (MIM) and in-source collision-induced dissociation (in source-CID) has been developed and applied to the characterization and quantitation of PLAs in rat plasma. First, PLAs will be fragmented into characteristic fragment ions under high declustering potential in the ionization source. The specific fragment ions are then screened twice by quadrupoles to ensure a high signal intensity and low interference for mass spectrometry detection. Subsequently, DMS technique has been applied to further reduce the background noise. The appropriately chosen surrogate specific precursor ions could be utilized for the qualitative and quantitative analysis of PLAs, which provided results with the advantages of low endogenous interference, sufficient sensitivity and selectivity for bioassay. The linearity of the method was evaluated over the concentration range 3-100 μg/mL (r² = 0.996) for PLA 20,000. The LC-DMS-MIM coupled with in source-CID strategy may contribute to the pharmaceutical studies of PLAs and the possible prospects of other pharmaceutical excipients.

Bioanalytical strategies in drug discovery and development

A reliable, rapid, and effective bioanalytical method is essential for the determination of the pharmacokinetic, pharmacodynamic, and toxicokinetic parameters that inform the safety and efficacy profile of investigational drugs. The overall goal of bioanalytical method development is to elucidate the procedure and operating conditions under which a method can sufficiently extract, qualify, and/or quantify the analyte(s) of interest and/or their metabolites for the intended purpose. Given the difference in the physicochemical properties of small and large molecule drugs, different strategies need to be adopted for the development of an effective and efficient bioanalytical method. Herein, we provide an overview of different sample preparation strategies, analytical platforms, as well as procedures for achieving high throughput for bioanalysis of small and large molecule drugs.

Intact plasma quantification of the large therapeutic lipopeptide bulevirtide

Bulevirtide is a first-in-class entry inhibitor of the hepatitis B and hepatitis delta virus blocking the sodium/bile acid co-transporter NTCP, and was recently approved for the treatment of hepatitis D as a priority medicine (prime) in an accelerated assessment by the European Medicines Agency. It is a very large lipopeptide comprising 47 amino acids in its sequence and a myristoylation at the N-terminus. For support of clinical development, we established highly sensitive plasma quantification assays using 100 μL of plasma, spanning concentrations of 0.1 to 100 ng/mL and 1 to 1000 ng/mL with the option to measure ten-fold diluted samples up to 10,000 ng/mL. Quantification was performed with UPLC-MS/MS measurements after extraction with protein precipitation. Both assays were fully validated according to the pertinent guidelines of the FDA and EMA, including incurred sample reanalyses and cross-validation using clinical study samples.

Ion Mobility–Mass Spectrometry for Bioanalysis

This paper aims to cover the main strategies based on ion mobility spectrometry (IMS) for the analysis of biological samples. The determination of endogenous and exogenous compounds in such samples is important for the understanding of the health status of individuals. For this reason, the development of new approaches that can be complementary to the ones already established (mainly based on liquid chromatography coupled to mass spectrometry) is welcomed. In this regard, ion mobility spectrometry has appeared in the analytical scenario as a powerful technique for the separation and characterization of compounds based on their mobility. IMS has been used in several areas taking advantage of its orthogonality with other analytical separation techniques, such as liquid chromatography, gas chromatography, capillary electrophoresis, or supercritical fluid chromatography. Bioanalysis is not one of the areas where IMS has been more extensively applied. However, over the last years, the interest in using this approach for the analysis of biological samples has clearly increased. This paper introduces the reader to the principles controlling the separation in IMS and reviews recent applications using this technique in the field of bioanalysis.

Application of triple quadrupole tandem mass spectrometry to the bioanalysis of collision-induced dissociation-resistant cyclic peptides - Ultra-sensitive quantification of the somatostatin-analog pasireotide utilizing UHPLC-MS/MS

Cyclic peptides are considered collision-induced dissociation (CID)-resistant due to immobile protons, and the necessity of at least two consecutive dissociation reactions to produce fragments with deviating m/z values. Therefore, the bioanalysis of cyclic peptides by tandem mass spectrometry (MS/MS) poses a major challenge, especially on triple quadrupole (TQ) instruments. One of these peptides is the somatostatin analog pasireotide, a cyclic hexapeptide administered to treat Cushing's disease and acromegaly. To support oral formulation development, sub-therapeutic quantification of pasireotide is highly beneficial. Regardless of the considered CID-resistance, we investigated the CID-characteristics of pasireotide and subsequently developed an ultra-sensitive UHPLC-MS/MS assay with a lower limit of quantification (LLOQ) of 5 pg/mL (4.9 pM) when using 100 μL of plasma and validated it according to the guidelines of the FDA and EMA. The achieved sensitivity, which is the highest thus far reported, demonstrates that TQ-MS/MS is a feasible approach to sensitive quantification of cyclic peptides despite their CID-resistance. Pasireotide was fast and efficiently extracted by protein depletion via precipitation using acetonitrile. Correlation coefficients > 0.99 were achieved for all calibration curves with linear regression. Inter-run and intra-run accuracy ranged from 89.4 to 99.3 % with corresponding precision of ≤ 7.5 % in the calibrated range, and from 94.6 to 105.6 % with corresponding precision of ≤ 14.5 % at the LLOQ. Quantification of 10-fold diluted samples showed an accuracy of 90.8 % and corresponding precision of 4.0 %. The assay was applied to the quantification of pasireotide plasma concentrations after intravenous administration to beagle dogs.

Discrimination of turmeric from different origins in China by MRM-based curcuminoid profiling and multivariate analysis

In this research, a three-step strategy was utilized for discriminating turmeric samples from different provinces and regions in China. Firstly, MRM-based UPLC-MS/MS method for chemical profiling of curcuminoids in turmeric samples was established. Then, response surface methodology was applied for optimizing the extraction process of targeted curcuminoids. Finally, multivariate analysis was conducted for systematic characterization of 66 curcuminoids in turmeric. Principal component analysis (PCA) and orthogonal projection to latent structure-discriminant analysis (OPLS-DA) revealed that turmeric samples from Sichuan and other regions could be classified into two distinct groups. Turmeric samples from the same group had similar curcuminoids content distribution. 25 differential curcuminoids were discovered through OPLS-DA, among which most curcuminoids were more abundant in Sichuan. Furthermore, turmeric samples from different provinces could be clearly discriminated based on hierarchical cluster analysis (HCA) using the screened differential curcuminoids.

Ultra-sensitive quantification of the therapeutic cyclic peptide bremelanotide utilizing UHPLC-MS/MS for evaluation of its oral plasma pharmacokinetics

Bremelanotide (Vyleesi®), a cyclic heptapeptide, was recently approved for the subcutaneous treatment of premenopausal hypoactive sexual desire disorder. To foster the development of alternative routes of administration, we aimed at determining the oral plasma pharmacokinetics of bremelanotide in beagle dogs. Therefore, we established a UHPLC-MS/MS assay with an LLOQ of 10 pg/mL (9.8 pM) using 100 μL of plasma and validated it according to the guidelines of the US Food and Drug Administration and the European Medicines Agency. Bremelanotide was isolated from plasma by protein precipitation and quantification was performed with positive heated ESI MS/MS in the SRM mode. The calibrated concentration range of 10-10,000 pg/mL was linear showing correlation coefficients > 0.99. In the calibrated range, interday and intraday accuracy ranged from 88.9-100.0 % with corresponding precision < 8 %. Accuracy at the LLOQ ranged from 93.6-100.8 % with corresponding precision < 11 %. Because of the validity of a dilution QC that showed accurate quantification of 10-fold diluted plasma samples (accuracy 99.4 %, precision < 6 %), the assay is suitable for bremelanotide quantification in its effective concentration range up to 100,000 pg/mL. The ultra-sensitive assay was applied to the quantification of bremelanotide plasma concentrations after oral administration to beagle dogs, which indicated minimal oral absorption.

Software-aided detection and structural characterization of cyclic peptide metabolites in biological matrix by high-resolution mass spectrometry

Compared to their linear counterparts, cyclic peptides show better biological activities, such as antibacterial, immunosuppressive, and anti-tumor activities, and pharmaceutical properties due to their conformational rigidity. However, cyclic peptides could form numerous putative metabolites from potential hydrolytic cleavages and their fragments are very difficult to interpret. These characteristics pose a great challenge when analyzing metabolites of cyclic peptides by mass spectrometry. This study was to assess and apply a software-aided analytical workflow for the detection and structural characterization of cyclic peptide metabolites. Insulin and atrial natriuretic peptide (ANP) as model cyclic peptides were incubated with trypsin/chymotrypsin and/or rat liver S9, followed by data acquisition using TripleTOF® 5600. Resultant full-scan MS and MS/MS datasets were automatically processed through a combination of targeted and untargeted peak finding strategies. MS/MS spectra of predicted metabolites were interrogated against putative metabolite sequences, in light of a, b, y and internal fragment series. The resulting fragment assignments led to the confirmation and ranking of the metabolite sequences and identification of metabolic modification. As a result, 29 metabolites with linear or cyclic structures were detected in the insulin incubation with the hydrolytic enzymes. Sequences of twenty insulin metabolites were further determined, which were consistent with the hydrolytic sites of these enzymes. In the same manner, multiple metabolites of insulin and ANP formed in rat liver S9 incubation were detected and structurally characterized, some of which have not been previously reported. The results demonstrated the utility of software-aided data processing tool in detection and identification of cyclic peptide metabolites.

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A software-aided workflow enabling detection and characterization of cyclic peptide metabolites by LC/HRMS.

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Automatically data processing through a combination of targeted and untargeted peak finding strategies.

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MS/MS spectra of predicted metabolites interrogated against putative metabolite sequences.

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Rapidly determining metabolite profiles of insulin and atrial natriuretic peptide in rat liver S9.

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Potentially applicable to metabolic soft spot analysis and in vitro metabolism across species in drug discovery.

Identification and quantification of amino acids and related compounds based on Differential Mobility Spectrometry

A new metabolite descriptor allowing fast quantification for the diagnosis of metabolic diseases.

Development of a quantitative method for four photocyanine isomers using differential ion mobility and tandem mass spectrometry and its application in a preliminary pharmacokinetics investigation

Photodynamic therapy (PDT) has been accepted as an alternative treatment for cancer, and its target specificity can be achieved by controlling the location at which light activates the photosensitizer. Photocyanine, a novel anticancer phthalocyanine-based photosensitizer, is a mixture of 4 cis-isomers of a series of synthetic products, and accordingly, it is essential to verify whether there are differences in pharmacokinetics among the four isomers for clinical application, which requires reliable analytical methods to measure the plasma concentrations of the four isomers. An efficient LC-MS/MS method coupled with differential mobility spectrometry (DMS) for the simultaneous quantification of the four photocyanine isomers in human plasma was developed and validated herein. This method had a limit of quantification of 10 ng mL^-1 for each isomer and showed stable and reproducible inter- and intra-day results. Use of this method in preliminary pharmacokinetic studies in patients with esophageal cancer showed that the exposure and distribution of the four isomers were different, which had not been found in previous studies. The present research revealed that DMS was an effective tool for isomeric quantitation and that LC-DMS-MS/MS presented robust and reliable in biomatrix analysis. The method significantly improved peak separation and sensitivity compared with that of other LC-MS-based methods.

Performance Enhancements in Differential Ion Mobility Spectrometry-Mass Spectrometry (DMS-MS) by Using a Modified CaptiveSpray Source

Differential ion mobility spectrometry (DMS) spatially separates ions in the gas phase using the mobility differences of the ions under applied low and high electric fields. The use of DMS as an ion filter (or ion selector) prior to mass spectrometry analysis has been compromised by the limited ion transmission efficiency. This paper reports enhancement of the DMS-MS sensitivity and signal stability using a modified CaptiveSpray™ source. In terms of the ion sampling and transmission efficiency, the modified CaptiveSpray source swept ~ 89% of the ions generated by the tapered capillary through the DMS device (compared to ~ 10% with a conventional microspray source). The signal fluctuation improved from 11.7% (relative standard deviation, RSD) with microspray DMS-MS to 3.6% using CaptiveSpray-DMS-MS. Coupling of LC to DMS-MS via the modified CaptiveSpray source was simple and robust. Using DMS as a noise-filtering device, LC-DMS-MS performed better than conventional LC-MS for analyzing a BSA digest standard. Although LC-DMS-MS had a lower sequence coverage (55%), a higher Mascot score (283) was obtained compared to those of LC-MS (sequence coverage 65%; Mascot score 192) under the same elution conditions. The improvement in the confidence of the search result was attributed to the preferential elimination of noise ions. Graphical Abstract ᅟ.

Resolution and Assignment of Differential Ion Mobility Spectra of Sarcosine and Isomers

Due to their central role in biochemical processes, fast separation and identification of amino acids (AA) is of importance in many areas of the biomedical field including the diagnosis and monitoring of inborn errors of metabolism and biomarker discovery. Due to the large number of AA together with their isomers and isobars, common methods of AA analysis are tedious and time-consuming because they include a chromatographic separation step requiring pre- or post-column derivatization. Here, we propose a rapid method of separation and identification of sarcosine, a biomarker candidate of prostate cancer, from isomers using differential ion mobility spectrometry (DIMS) interfaced with a tandem mass spectrometer (MS/MS) instrument. Baseline separation of protonated sarcosine from α- and β-alanine isomers can be easily achieved. Identification of DIMS peak is performed using an isomer-specific activation mode where DIMS- and mass-selected ions are irradiated at selected wavenumbers allowing for the specific fragmentation via an infrared multiple photon dissociation (IRMPD) process. Two orthogonal methods to MS/MS are thus added, where the MS/MS(IRMPD) is nothing but an isomer-specific multiple reaction monitoring (MRM) method. The identification relies on the comparison of DIMS-MS/MS(IRMPD) chromatograms recorded at different wavenumbers. Based on the comparison of IR spectra of the three isomers, it is shown that specific depletion of the two protonated α- and β-alanine can be achieved, thus allowing for clear identification of the sarcosine peak. It is also demonstrated that DIMS-MS/MS(IRMPD) spectra in the carboxylic C=O stretching region allow for the resolution of overlapping DIMS peaks. Graphical Abstract ᅟ.

2017 White Paper on recent issues in bioanalysis: aren't BMV guidance/guidelines ‘Scientific’? (Part 1 – LCMS: small molecules, peptides and small molecule biomarkers)

The 2017 11th Workshop on Recent Issues in Bioanalysis (11th WRIB) took place in Los Angeles/Universal City, California from 3 April 2017 to 7 April 2017 with participation of close to 750 professionals from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day, weeklong event – A Full Immersion Week of Bioanalysis, Biomarkers and Immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small and large molecule analysis involving LCMS, hybrid LBA/LCMS and ligand-binding assay (LBA) approaches. This 2017 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2017 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1) covers the recommendations for Small Molecules, Peptides and Small Molecule Biomarkers using LCMS. Part 2 (Biotherapeutics, Biomarkers and Immunogenicity Assays using Hybrid LBA/LCMS and Regulatory Agencies’ Inputs) and Part 3 (LBA: Immunogenicity, Biomarkers and PK Assays) are published in volume 9 of Bioanalysis, issues 23 and 24 (2017), respectively.

Analysis of 17β-estradiol, estriol and estrone in American eel (Anguilla rostrata) tissue samples using liquid chromatography coupled to electrospray differential ion mobility tandem mass spectrometry

RATIONALE

17β-Estradiol (E2), estrone (E1) and estriol (E3) are steroid hormones responsible for the regulation of the female reproductive system. Estradiol is planned to be used to feminize eels in aquaculture in order to improve their size and marketability. The residual levels of these hormones in fish tissue must be monitored to meet the requirements of food regulatory agencies. Few studies have studied these hormones in complex biological matrices such as fish tissue.

METHODS

We developed a method to analyze E1, E2 and E3 in fish tissue using liquid chromatography in combination with differential ion mobility spectrometry (DMS) and tandem mass spectrometry (MS/MS). The mass spectrometer was operated in negative polarity selected reaction monitoring (SRM) mode. To test the performance of this method, residual levels of E1, E2 and E3 were measured in the muscle tissue of juvenile eels subjected to feminization treatment with E2.

RESULTS

We report that following 17β-estradiol treatment, E2 is rapidly metabolized from the eel tissue, with a 50% depletion rate per day. Five days post-treatment, E2 returned to the level found in non-treated controls, similar to levels found in wild mature female eels.

CONCLUSIONS

The method presented herein allows the quantitative analysis of E1, E2 and E3 in fish tissue samples. Under the experimental conditions, E2 in fish tissue samples returned to physiological levels post hormonal treatment. Copyright © 2017 John Wiley & Sons, Ltd.

Differential mobility spectrometry combined with multiple ion monitoring for bioanalysis of disulfide-bonded peptides with inefficient collision-induced dissociation fragmentation

Aim: It is challenging to develop a multiple reaction monitoring (MRM) method for some disulfide-bonded peptides with inefficient collision-induced dissociation fragmentation. This study describes a new methodology using differential mobility spectrometry (DMS) combined with multiple ion monitoring (MIM) to enhance bioanalytical sensitivity for sunflower trypsin inhibitor. Results: By combining DMS with MIM to monitor the intact precursor ion in Q1 and Q3 MS analyzers, a lower limit of quantitation at 0.125 ng/ml was achieved to quantify sunflower trypsin inhibitor in rat plasma, representing a 40-fold sensitivity improvement over MIM without DMS. Conclusion: DMS coupled with MIM method provides triple quadrupole MS users an effective means to overcome challenges in analyzing disulfide-bonded peptides or other analytes that do not have useful collision-induced dissociation fragment ions for MRM analysis.

HRMS using a Q-Exactive series mass spectrometer for regulated quantitative bioanalysis: how, when, and why to implement

High-resolution MS (HRMS) has seen an uptake in use for discovery qual/quan workflows, however, its utilization in late discovery/development has been slow. Past reports comparing HRMS to triple quadrupole (QQQ) instrumentation to date have indicated that HRMS instruments are capable of producing data acceptable for regulated bioanalysis, however lack the sensitivity required for sub ng/ml LLOQ assays. Recent advances in HRMS instrumentation have closed the sensitivity gap with QQQ and have even provided improved selectivity and sensitivity over QQQ SRM assays. Herein, the authors will describe how, when, and why HRMS (specifically Q-Exactive series mass spectrometers) should be considered for implementation in regulated quantitative bioanalysis assays.