Optimizing Messenger RNA Analysis Using Ultra-Wide Pore Size Exclusion Chromatography Columns.

Biopharmaceutical products, in particular messenger ribonucleic acid (mRNA), have the potential to dramatically improve the quality of life for patients suffering from respiratory and infectious diseases, rare genetic disorders, and cancer. However, the quality and safety of such products are particularly critical for patients and require close scrutiny. Key product-related impurities, such as fragments and aggregates, among others, can significantly reduce the efficacy of mRNA therapies. In the present work, the possibilities offered by size exclusion chromatography (SEC) for the characterization of mRNA samples were explored using state-of-the-art ultra-wide pore columns with average pore diameters of 1000 and 2500 Å. Our investigation shows that a column with 1000 Å pores proved to be optimal for the analysis of mRNA products, whatever the size between 500 and 5000 nucleotides (nt). We also studied the influence of mobile phase composition and found that the addition of 10 mM magnesium chloride (MgCl2) can be beneficial in improving the resolution and recovery of large size variants for some mRNA samples. We demonstrate that caution should be exercised when increasing column length or decreasing the flow rate. While these adjustments slightly improve resolution, they also lead to an apparent increase in the amount of low-molecular-weight species (LMWS) and monomer peak tailing, which can be attributed to the prolonged residence time inside the column. Finally, our optimal SEC method has been successfully applied to a wide range of mRNA products, ranging from 1000 to 4500 nt in length, as well as mRNA from different suppliers and stressed/unstressed samples.

High-Throughput Chromatographic Separation of Oligonucleotides: A Proof of Concept Using Ultra-Short Columns.

Ion-pairing reversed-phase liquid chromatography (IP-RPLC) is the reference separation technique for characterizing oligonucleotides (ONs) and their related impurities. The aim of this study was to better understand the retention mechanism of ONs, evaluate the applicability of the linear solvent strength (LSS) retention model, and explore the potential of ultra-short columns having a length of only 5 mm for the separation of model ONs. First, the validity of the LSS model was evaluated for ONs having sizes comprised between 3 and 30 kDa, and the accuracy of retention time predictions was assessed. It was found that ONs in IP-RPLC conditions follow an "on-off" elution behavior, despite a molecular weight lower than that of proteins. For most linear gradient separation conditions, a column length between 5 and 35 mm was found to be appropriate. Ultra-short columns of only 5 mm were therefore explored to speed up separations by considering the impact of the instrumentation on the efficiency. Interestingly, the impacts of injection volume and post-column connection tubing on peak capacity were found to be negligible. Finally, it was demonstrated that longer columns would not improve selectivity or separation efficiency, but baseline separation of three model ONs mixtures was enabled in as little as 30 s on the 5 mm column. This proof-of-concept work paves the way for future investigations using more complex therapeutic ONs and their related impurities.

Boosting the Separation of Adeno-Associated Virus Capsid Proteins by Liquid Chromatography and Capillary Electrophoresis Approaches.

The purity of the three capsid proteins that make up recombinant adeno-associated virus (rAAV) is considered a critical quality attribute of gene therapy products. As such, there is a clear need to develop separation methods capable of rapidly characterizing these three viral proteins (VPs). In this study, the potential benefits and limitations of different electrophoretic and chromatographic methods were evaluated, including capillary electrophoresis-sodium dodecyl sulfate (CE-SDS), reversed phase liquid chromatography (RPLC), hydrophilic interaction chromatography (HILIC), and hydrophobic interaction chromatography (HIC), for the analysis of VPs obtained from different serotypes (i.e., AAV2, AAV5, AAV8, and AAV9). CE-SDS is considered to be the reference method and provides a suitable separation of VP1-3 proteins using generic conditions and laser induced fluorescence detection. However, the characterization of post-translational modifications (i.e., phosphorylation, oxidation) remains difficult, and species identification is almost impossible due to the lack of compatibility between CE-SDS and mass spectrometry (MS). In contrast, RPLC and HILIC were found to be less generic than CE-SDS and require tedious optimization of the gradient conditions for each AAV serotype. However, these two chromatographic approaches are inherently compatible with MS, and were shown to be particularly sensitive in detecting capsid protein variants resulting from different post-translational modifications. Finally, despite being non-denaturing, HIC offers disappointing performance for viral capsid proteins characterization.

Enhancing Selectivity of Protein Biopharmaceuticals in Ion Exchange Chromatography through Addition of Organic Modifiers.

Charge heterogeneity among therapeutic monoclonal antibodies (mAbs) is considered an important critical quality attribute and requires careful characterization to ensure safe and efficacious drug products. The charge heterogeneity among mAbs is the result of chemical and enzymatic post-translational modifications and leads to the formation of acidic and basic variants that can be characterized using cation exchange chromatography (CEX). Recently, the use of mass spectrometry-compatible salt-mediated pH gradients has gained increased attention to elute the proteins from the charged stationary phase material. However, with the increasing antibody product complexity, more and more selectivity is required. Therefore, in this study, we set out to improve the selectivity by using a solvent-enriched mobile phase composition for the analysis of a variety of mAbs and bispecific antibody products. It was found that the addition of the solvents to the mobile phase appeared to modify the hydrate shell surrounding the protein and alter the retention behavior of the studied proteins. Therefore, this work demonstrates that the use of solvent-enriched mobile phase composition could be an attractive additional method parameter during method development in CEX.

Tackling Issues Observed during the Development of a Liquid Chromatography Method for Small Molecule Quantification in Antibody-Chelator Conjugate.

In the context of targeted radionuclide therapy, antibody-chelator conjugates (ACCs) are an evolving class of antibody-related drugs with promising applications as tumor-targeted pharmaceuticals. Generally, a typical ACC consists of a recombinant monoclonal antibody (mAb) coupled to radionuclide via a chelating agent. Characterizing the ACC structure represents an analytical challenge since various impurities must be constantly monitored in the presence of formulation components during the quality control (QC) process. In this contribution, a reliable method devoted to the monitoring of an ACC sample, and its small molecule-related synthesis impurities, has been developed via liquid chromatography (LC). A problem-solving approach of common analytical issues was used to highlight some major issues encountered during method development. This included separation of poorly retained impurities (issue #1); interferences from the formulation components (issue #2); analysis of impurities in presence of ACC at high concentration (issue #3); and recovery of impurities during the whole analytical procedure (issue #4). To the best of our knowledge, this is the first time that a chromatographic method for the analysis of ACC synthesis impurities is presented. In addition, the developed approach has the potential to be more widely applied to the characterization of similar ACCs and other antibody-related drugs.

Interlaboratory Evaluation of a User-Friendly Benchtop Mass Spectrometer for Multiple-Attribute Monitoring Studies of a Monoclonal Antibody.

In the quest to market increasingly safer and more potent biotherapeutic proteins, the concept of the multi-attribute method (MAM) has emerged from biopharmaceutical companies to boost the quality-by-design process development. MAM strategies rely on state-of-the-art analytical workflows based on liquid chromatography coupled to mass spectrometry (LC-MS) to identify and quantify a selected series of critical quality attributes (CQA) in a single assay. Here, we aimed at evaluating the repeatability and robustness of a benchtop LC-MS platform along with bioinformatics data treatment pipelines for peptide mapping-based MAM studies using standardized LC-MS methods, with the objective to benchmark MAM methods across laboratories, taking nivolumab as a case study. Our results evidence strong interlaboratory consistency across LC-MS platforms for all CQAs (i.e., deamidation, oxidation, lysine clipping and glycosylation). In addition, our work uniquely highlights the crucial role of bioinformatics postprocessing in MAM studies, especially for low-abundant species quantification. Altogether, we believe that MAM has fostered the development of routine, robust, easy-to-use LC-MS platforms for high-throughput determination of major CQAs in a regulated environment.

Direct coupling of size exclusion chromatography and mass spectrometry for the characterization of complex monoclonal antibody products.

The present study describes the possibilities offered by an innovative bioinert size exclusion chromatography column for size variant characterization of complex monoclonal antibody products. This size exclusion chromatography column includes a novel column hardware surface. The column was prepared from metallic hardware components that were treated to have prototype hydrophilically modified hybrid organic-inorganic silica surfaces called hybrid surface technology. This provides a significant reduction in nondesired hydrophobic and electrostatic interactions that can occur between column and analyte when performing size exclusion chromatography analysis with volatile mobile phase. Compared to a reference stainless-steel column packed with the same batch of packing material, peak tailing, band broadening, and above all recovery of high molecular weight species were distinctly improved for all types of monoclonal antibody products. Based on our observations, we found that 50 mM ammonium acetate in water was a suitable mobile phase offering good compromise in terms of liquid chromatography performance and mass spectrometry sensitivity. In addition, method repeatability (intra- and interday relative standard deviations) on elution times and high molecular weight species peak areas were found to be excellent. By using this innovative size exclusion chromatography material, the low and high molecular weight species contained in various stressed and nonstressed monoclonal antibody products were successfully characterized with mass spectrometry detection.

Anion-Exchange Chromatography at the Service of Gene Therapy: Baseline Separation of Full/Empty Adeno-Associated Virus Capsids by Screening of Conditions and Step Gradient Elution Mode.

Gene therapy is opening unprecedented opportunities for novel therapeutic approaches. Based on the concept of rescuing function mutations by co-expressing the correct gene to allow biological functions to be restored, it requires the use of viral vectors to ensure the proper delivery of therapeutic genes. In this context, recombinant adeno-associated viruses (rAAV) are the most widely used vectors. Their biomanufacturing process requires the insertion of the therapeutic gene into the rAAV (full capsids). However, a percentage of rAAV that do not contain the desired gene (empty capsids), as well as partly filled capsids, might also be produced, potentially impacting the efficiency of the therapy. Therefore, the determination of the rAAV capsids' full/empty ratio needs to be monitored to ensure consistent product quality and efficacy. Anion-exchange chromatography (AEX) can serve this need. In this contribution, thorough AEX method development, including a mobile phase, a stationary phase and gradient conditions, has highlighted its potential in supporting gene therapy. Taking advantage of the fact that viral capsids follow an "on/off" retention behavior, the application of a step gradient approach to the rAAV serotype 8 (rAAV8) allowed the unprecedented separation of rAAV8 full/empty capsids, with a resolution gain of 3.7 as compared to the resolution obtained with a fully optimized linear gradient. Finally, the developed analytical approach allowed a precise and accurate baseline separation and quantification of full and empty rAAV8 capsids, with the potential to be applied as a high-throughput quality control (QC) method.

Therapeutic Fc-fusion proteins: Current analytical strategies.

Fc-Fusion proteins represent a successful class of biopharmaceutical products, with already 13 drugs approved in the European Union and United States as well as three biosimilar versions of etanercept. Fc-Fusion products combine tailored pharmacological properties of biological ligands, together with multiple functions of the fragment crystallizable domain of immunoglobulins. There is a great diversity in terms of possible biological ligands, including the extracellular domains of natural receptors, functionally active peptides, recombinant enzymes, and genetically engineered binding constructs acting as cytokine traps. Due to their highly diverse structures, the analytical characterization of Fc-Fusion proteins is far more complex than that of monoclonal antibodies and requires the use and development of additional product-specific methods over conventional generic/platform methods. This can be explained, for example, by the presence of numerous sialic acids, leading to high diversity in terms of isoelectric points and complex glycosylation profiles including multiple N- and O-linked glycosylation sites. In this review, we highlight the wide range of analytical strategies used to fully characterize Fc-fusion proteins. We also present case studies on the structural assessment of all commercially available Fc-fusion proteins, based on the features and critical quality attributes of their ligand-binding domains.

Glycan-Mediated Technology for Obtaining Homogeneous Site-Specific Conjugated Antibody-Drug Conjugates: Synthesis and Analytical Characterization by Using Complementary Middle-up LC/HRMS Analysis.

Conventional antibody-drug conjugate (ADC) manufacturing methods are based on the nonselective bioconjugation of cytotoxic drugs to lysine and cysteine residues. This results in highly heterogeneous mixtures of different drug-antibody ratios (DAR) that can significantly affect the safety and efficacy of the ADC product. Recently, an innovative procedure named GlyCLICK was suggested, consisting of a two-step enzymatic procedure to transform Fc-glycans present on IgG mAbs into two site-specific anchor points for the conjugation of any alkyne-containing payload of choice. Here, we evaluated the conjugation process by comparing trastuzumab and trastuzumab conjugated with DM1, following the GlyCLICK procedure. Complementary reversed phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC) coupled to high-resolution mass spectrometry (HRMS) were used to analyze the protein subunits (ca. 25-100 kDa) obtained after different levels of enzymatic digestion and chemical reduction. Our results demonstrated that the hydrophobic character of the drug molecule allows to rapidly confirm the Fc-drug conjugation at the chromatographic level. Furthermore, the hyphenation to MS detection provided accurate mass information on the ADC subunits and facilitated the DAR determination of 2.0. Therefore, this work illustrates how middle-up analysis using LC/HRMS can provide accurate and complementary information on the critical quality attributes of these novel site-specific ADC products.

Interlaboratory and Interplatform Study of Steroids Collision Cross Section by Traveling Wave Ion Mobility Spectrometry.

Collision cross section (CCS) databases based on single-laboratory measurements must be cross-validated to extend their use in peak annotation. This work addresses the validation of the first comprehensive TWCCSN2 database for steroids. First, its long-term robustness was evaluated (i.e., a year and a half after database generation; Synapt G2-S instrument; bias within ±1.0% for 157 ions, 95.7% of the total ions). It was further cross-validated by three external laboratories, including two different TWIMS platforms (i.e., Synapt G2-Si and two Vion IMS QToF; bias within the threshold of ±2.0% for 98.8, 79.9, and 94.0% of the total ions detected by each instrument, respectively). Finally, a cross-laboratory TWCCSN2 database was built for 87 steroids (142 ions). The cross-laboratory database consists of average TWCCSN2 values obtained by the four TWIMS instruments in triplicate measurements. In general, lower deviations were observed between TWCCSN2 measurements and reference values when the cross-laboratory database was applied as a reference instead of the single-laboratory database. Relative standard deviations below 1.5% were observed for interlaboratory measurements (<1.0% for 85.2% of ions) and bias between average values and TWCCSN2 measurements was within the range of ±1.5% for 96.8% of all cases. In the context of this interlaboratory study, this threshold was also suitable for TWCCSN2 measurements of steroid metabolites in calf urine. Greater deviations were observed for steroid sulfates in complex urine samples of adult bovines, showing a slight matrix effect. The implementation of a scoring system for the application of the CCS descriptor in peak annotation is also discussed.

The Emergence of Universal Chromatographic Methods in the Research and Development of New Drug Substances.

Manufacturing process development of new drug substances in the pharmaceutical industry combines numerous chemical challenges beyond the efficient synthesis of complex molecules. Optimization of a synthetic route involves the screening of multiple reaction variables with a desired outcome that not only depends on an increased product yield but is also highly influenced by the removal efficacy of residual chemicals and reaction byproducts during the subsequent synthetic route. Consequently, organic chemists must survey a wide array of synthetic variables to develop a highly productive, green, and cost-effective manufacturing process. The time constraints of developing robust quantitative methods prior to each processing step can easily lead to sample analysis becoming a bottleneck in synthetic route development. In this regard, conventional "on demand" analytical method development and optimization approaches, traditionally used for guiding synthetic chemistry efforts, become unsustainable. This Account introduces recent efforts to address the aforementioned challenges through the development and implementation of generic or more universal chromatographic methods that can cover a broad spectrum of targeted compound classes. Such generic methods require significant resolving power to enable baseline resolution of multicomponent mixtures in a single experimental run without additional method customization but must be simple enough to allow for routine use by chemists, chemical engineers and other researchers with little experience in chromatographic method development. These powerful analytical methodologies are often employed to minimize the time spent developing new analytical assays, while also facilitating method transfer to manufacturing facilities and application in regulatory settings. Diverse examples of universal and fit-for-purpose analytical procedures are presented herein, illustrating the power of modern readily available analytical technology for streamlining the development of new drug substances in organic chemistry laboratories across both academic and industrial sectors. With recent advances in analytical instrumentation and column technologies, universal chromatographic methods are quickly becoming a proactive and effective strategy to accelerate the discovery and implementation of new synthetic methodologies, especially but not limited to laboratories where the synthetic process route is undergoing rapid change and optimization. Targets of these generic methods include analysis of organic solvents, acid and basic additives, nucleotide species, palladium scavengers, impurity mapping, enantiopurity, synthetic intermediates, active pharmaceutical ingredients and their counterions, dehalogenation byproducts, and mixtures of organohalogenated pharmaceuticals, among other chemicals used or formed in process chemistry reactions.

Orthogonal Middle-up Approaches for Characterization of the Glycan Heterogeneity of Etanercept by Hydrophilic Interaction Chromatography Coupled to High-Resolution Mass Spectrometry.

Etanercept is a recombinant Fc fusion protein widely used to treat rheumatic diseases. This protein is highly glycosylated and contains numerous O- and N-glycosylation sites. Since glycosylation is recognized as an important critical quality attribute (CQA) that can affect immunogenicity, solubility, and stability of Fc fusion proteins, it should be thoroughly characterized. In this work, hydrophilic interaction chromatography (HILIC) was combined with high-resolution mass spectrometry (HRMS) by using a quadrupole time-of flight mass spectrometer to assess glycosylation of etanercept at the middle-up level of analysis (fragments of ca. 25-30 kDa). In addition, a combination of different enzymatic digestion procedures (i.e., glycosidase, sialidase, and protease) was systematically employed to facilitate spectra deconvolution. With the developed procedure, the main post-translational modifications (PTMs) of etanercept were assessed, and a global overview of the subunit-specific distribution of the glycosylation pattern was obtained at a middle-up level of analysis.

Cutting-edge multi-level analytical and structural characterization of antibody-drug conjugates: present and future.

INTRODUCTION: The development and optimization of antibody drug conjugates (ADCs) rely on improving their analytical and bioanalytical characterization, by assessing critical quality attributes (CQAs). Among the CQAs, the glycoprofile, drug load distribution (DLD), the amount of unconjugated antibody (D0), the average drug-to-antibody ratio (DAR), the drug conjugation sites and the residual drug-linker and related product proportions (SMDs) in addition to high and low molecular weight species (H/LMWS), and charge variants are the most important ones. Areas covered: The analytical and structural toolbox for the characterization of 1st, 2d and 3d generation ADCs was significantly extended in the last 3 years. Here, we reviewed state-of-the-art techniques, such as liquid chromatography, high resolution native and ion mobility mass spectrometry, multidimensional liquid chromatography and capillary electrophoresis hyphenated to mass spectrometry, reported mainly since 2016. Expert commentary: These emerging techniques allow a deep insight into important CQAs that are related to ADC Chemistry Manufacturing and Control (CMC) as well as an improved understanding of in vitro and in vivo ADC biotransformations. This knowledge and the development of quantitative bioanalytical assays will continue to contribute to early-developability assessment for the optimization of all the ADC components (i.e. antibody, drug, and linker) and help to bring next-generation ADCs into late clinical development and to the market.

DNA and RNA telomeric G-quadruplexes: what topology features can be inferred from ion mobility mass spectrometry?

Maintenance of the telomeres is key to chromosome integrity and cell proliferation. The G-quadruplex structures formed by telomeric DNA and RNA (TTAGGG and UUAGGG repeats, respectively) are key to this process. However, because these sequences are particularly polymorphic, solving high-resolution structures is not always possible, and there is a need for new methodologies to characterize the multiple structures coexisting in solution. In this context, we evaluated whether ion mobility spectrometry coupled to native mass spectrometry could help separate and assign the G-quadruplex topologies. We explored the circular dichroism spectra, multimer formation, cation binding, and ion mobility spectra of several 4-repeat and 8-repeat telomeric DNA and RNA sequences, both in NH4+ and in K+. In 1 mM K+ and 100 mM trimethylammonium acetate, all RNAs fold intramolecularly (no multimer). In 8-repeat sequences, the subunits are not independent: in DNA the first subunit disfavors the folding of the second one, whereas in RNA the two subunits fold cooperatively via cation-mediated stacking. Ion mobility spectrometry shows that gas-phase structures keep a memory of - but are not identical to - the solution ones. At the native charge states, the loops can rearrange in a variety of ways (unless they are constrained by pre-formed hydrogen bonds), thereby wrapping the core and masking the strand arrangements. Our study highlights that, to progress towards structural assignment from IM-MS experiments, deeper understanding of the solution-to-gas-phase rearrangement mechanisms is warranted.

A generic workflow for the characterization of therapeutic monoclonal antibodies-application to daratumumab.

In the present analytical workflow, chromatographic methods have been developed and hyphenated to mass spectrometry (MS) for the characterization of protein size, charge, hydrophobic, and hydrophilic variants of daratumumab. Multiple critical quality attributes (CQAs) were characterized in forced degraded daratumumab sample, using size exclusion, ion exchange (IEX), and hydrophobic interaction (HIC) chromatography coupled to fluorescence detection for relative quantification and fractionation. Mass assignment was performed by using a fast, non-denaturing and universal size exclusion chromatography (SEC) method prior to native MS analysis of the collected fractions (off-line approach). This allowed the identification of N-terminal lysine clipping, and the extent of glycation and oxidation at intact protein level. Finally, middle-up analysis of daratumumab was performed using reversed phase (RPLC) and hydrophilic interaction (HILIC) chromatography coupled to MS to obtain a comprehensive overview of all PTMs after the forced stressed conditions and a fine characterization of the glycosylation profile. Conveniently, the presented workflow maintains the established golden standard non-denaturing chromatography techniques and additionally introduces a straightforward and automated desalting procedure prior to MS analysis. Therefore, it is expected that the off-line coupling of SEC, IEX, and HIC to SEC-MS has great potential to be implemented in routine characterization of mAbs. Graphical abstract ᅟ.

A Novel Online Four-Dimensional SEC×SEC-IM×MS Methodology for Characterization of Monoclonal Antibody Size Variants.

The determination of size variants is a major critical quality attribute of a therapeutic monoclonal antibody (mAb that may affect the drug product safety, potency, and efficacy. Size variant characterization often relies on size-exclusion chromatography (SEC), which could be hampered by difficult identification of peaks. On the other hand, mass spectrometry (MS)-based techniques performed in nondenaturing conditions have proven to be valuable for mAb-related compound characterization. On the basis of the observation that limited SEC performance was observed in nondenaturing MS compatible ammonium acetate buffer compared with classical phosphate salts, a multidimensional analytical approach was proposed. It combines comprehensive online two-dimensional chromatography (SEC×SEC), with ion mobility and mass spectrometry (IM-MS) in nondenaturing conditions for the characterization of a variety of mAbs. We first exemplify the versatility of our approach for simultaneous detection, identification, and quantitation of adalimumab size variants. Benefits of the SEC×SEC-native IM×MS were further highlighted on forced degraded pembrolizumab and bevacizumab samples, for which the 4D setup was mandatory to obtain an extensive and unambiguous identification, and accurate quantitation of unexpected high/low molecular weight species (HMWS and LMWS). In this specific context, monomeric conformers were detected by IM-MS as HMWS or LMWS. Altogether, our results emphasize the power of comprehensive 2D LC×LC setups hyphenated to IM×MS in nondenaturing conditions with unprecedented performance including: (i) maintaining optimal SEC performance (under classical nonvolatile salt conditions), (ii) performing online native MS identification, and (iii) providing IM-MS conformational characterization of all separated size variants.

An Online Four-Dimensional HIC×SEC-IM×MS Methodology for Proof-of-Concept Characterization of Antibody Drug Conjugates.

There are currently two main techniques allowing the analytical characterization of interchain cysteine-linked antibody drug conjugates (ADCs) under native conditions, namely, hydrophobic interaction chromatography (HIC) and native mass spectrometry (MS). HIC is a chromatographic technique allowing the evaluation of drug load profile and calculation of average drug-to-antibody ratio (DAR) in quality control laboratories. Native MS offers structural insights into multiple ADC critical quality attributes, thanks to accurate mass measurement. However, both techniques can lead to misinterpretations or incomplete characterization when used as standalone methods. Online coupling of both techniques can thus potentially be of great interest, but the presence of large amounts of nonvolatile salts in HIC mobile phases makes it not easily directly compatible with native MS. Here, we present an innovative multidimensional analytical approach combining comprehensive online two-dimensional (2D)-chromatography that consists of HIC and size-exclusion chromatography (SEC), to ion mobility and mass spectrometry (IM-MS) for performing analytical characterization of ADCs under nondenaturing conditions. This setup enabled comprehensive and streamlined characterization of both native and forced degraded ADC samples. The proposed 4D methodology might be more generally adapted for online all-in-one HIC×SEC-IM×MS analysis of single proteins or analysis of protein complexes in nondenaturing conditions.

Adding a new separation dimension to MS and LC-MS: What is the utility of ion mobility spectrometry?

Ion mobility spectrometry is an analytical technique known for more than 100 years, which entails separating ions in the gas phase based on their size, shape, and charge. While ion mobility spectrometry alone can be useful for some applications (mostly security analysis for detecting certain classes of narcotics and explosives), it becomes even more powerful in combination with mass spectrometry and high-performance liquid chromatography. Indeed, the limited resolving power of ion mobility spectrometry alone can be tackled when combining this analytical strategy with mass spectrometry or liquid chromatography with mass spectrometry. Over the last few years, the hyphenation of ion mobility spectrometry to mass spectrometry or liquid chromatography with mass spectrometry has attracted more and more interest, with significant progresses in both technical advances and pioneering applications. This review describes the theoretical background, available technologies, and future capabilities of these techniques. It also highlights a wide range of applications, from small molecules (natural products, metabolites, glycans, lipids) to large biomolecules (proteins, protein complexes, biopharmaceuticals, oligonucleotides).

Hydrophilic Interaction Chromatography Hyphenated with Mass Spectrometry: A Powerful Analytical Tool for the Comparison of Originator and Biosimilar Therapeutic Monoclonal Antibodies at the Middle-up Level of Analysis.

The development and approval processes of biosimilar mAbs depend on their comparability to originators. Therefore, analytical comparisons are required to assess structural features and post-translational modifications (PTM) and thereby minimize the risk of being clinically meaningful differences between biosimilar and originator drug products. The glycosylation pattern of mAbs is considered to be an important critical quality attribute (CQA), and several analytical approaches have been proposed that facilitate characterizing and monitoring a glycosylation profile, albeit mainly at a glycan and glycopeptide level of analysis. In this study, we demonstrate the utility of hydrophilic interaction chromatography (HILIC) hyphenated with mass spectrometry (MS) for the qualitative profiling of glycosylation patterns at the protein level, by comparing originator and biosimilars mAbs (Remicade/Remsina/Inflectra, Herceptin/Trastuzumab B, and Erbitux/Cetuximab B) using a middle-up approach. We demonstrate the ability of HILIC to resolve hydrophilic variants of protein biopharmaceuticals at the middle-up level of analysis, its complementarity to reversed phase liquid chromatography, and its hyphenation to MS. HILIC features combined to MS make a powerful analytical tool for the comparison of originator and biosimilar mAbs that could eventually be applied in routine analyses for quality control.