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Wu Y, Gardner R, Schöneich C. Near UV and Visible Light-Induced Degradation of Bovine Serum Albumin and a Monoclonal Antibody Mediated by Citrate Buffer and Fe(III): Reduction vs Oxidation Pathways. Mol Pharm 2024; 21:4060-4073. [PMID: 39013609 DOI: 10.1021/acs.molpharmaceut.4c00445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Light exposure during manufacturing, storage, and administration can lead to the photodegradation of therapeutic proteins. This photodegradation can be promoted by pharmaceutical buffers or impurities. Our laboratory has previously demonstrated that citrate-Fe(III) complexes generate the •CO2- radical anion when photoirradiated under near UV (λ = 320-400 nm) and visible light (λ = 400-800 nm) [Subelzu, N.; Schöneich, C. Mol. Pharmaceutics 2020, 17 (11), 4163-4179; Zhang, Y. Mol. Pharmaceutics 2022, 19 (11), 4026-4042]. Here, we evaluated the impact of citrate-Fe(III) on the photostability and degradation mechanisms of disulfide-containing proteins (bovine serum albumin (BSA) and NISTmAb) under pharmaceutically relevant conditions. We monitored and localized competitive disulfide reduction and protein oxidation by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis depending on the reaction conditions. These competitive pathways were affected by multiple factors, including light dose, Fe(III) concentration, protein concentration, the presence of oxygen, and light intensity.
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Affiliation(s)
- Yaqi Wu
- Department of Pharmaceutical Chemistry, The University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Reece Gardner
- Summer Undergraduate Research Program, Department of Pharmaceutical Chemistry, The University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, The University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
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2
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Zhang Y, Richards DS, Schöneich C. Near UV Light Photo-Degradation of Lactate and Related α-Hydroxycarboxylates in the Presence of Fe(III): Formation of Carbon Dioxide Radical Anion. J Pharm Sci 2024:S0022-3549(24)00243-0. [PMID: 39002725 DOI: 10.1016/j.xphs.2024.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/25/2024] [Accepted: 06/25/2024] [Indexed: 07/15/2024]
Abstract
In recent studies we have reported on the near-UV light-induced degradation of iron complexes of various pharmaceutical excipients, such as Fe(III)-citrate and Fe(III)-amino acid complexes. Mechanistic studies revealed a common photo-degradation pattern, i.e. the formation of carbon dioxide radical anion, a potent reducing agent, via an alkoxyl/amino radical intermediate generated by light-induced ligand-to-metal charge transfer (LMCT) involving α-hydroxycarboxylates or amino acids. Herein, we confirm the proposed general photo-degradation pathways through the study of the iron complexes of other α-hydroxycarboxylates that may be present in protein formulations, such as lactate and glycolate. The results indicate that lactate generates even higher yields of •CO2- as compared to citrate, suggesting a significant potential of lactate for the promotion of photo-degradation in pharmaceutical formulations.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
| | - David S Richards
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA.
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3
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Lv JY, Ingle RG, Wu H, Liu C, Fang WJ. Histidine as a versatile excipient in the protein-based biopharmaceutical formulations. Int J Pharm 2024; 662:124472. [PMID: 39013532 DOI: 10.1016/j.ijpharm.2024.124472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 07/03/2024] [Accepted: 07/12/2024] [Indexed: 07/18/2024]
Abstract
Adequate stabilization is essential for marketed protein-based biopharmaceutical formulations to withstand the various stresses that can be exerted during the pre- and post-manufacturing processes. Therefore, a suitable choice of excipient is a significant step in the manufacturing of such delicate products. Histidine, an essential amino acid, has been extensively used in protein-based biopharmaceutical formulations. The physicochemical properties of histidine are unique among amino acids and could afford multifaceted benefits to protein-based biopharmaceutical formulations. With a pKa of approximately 6.0 at the side chain, histidine has been primarily used as a buffering agent, especially for pH 5.5-6.5. Additionally, histidine exhibited several affirmative properties similar to those of carbohydrates (e.g., sucrose and trehalose) and could therefore be considered to be an alternative approach to established protein-based formulation strategies. The current review describes the general physicochemical properties of histidine, lists all commercial histidine-containing protein-based biopharmaceutical products, and discusses a brief outline of the existing research focused on the versatile applications of histidine, which can act as a buffering agent, stabilizer, cryo-/lyo-protectant, antioxidant, viscosity reducer, and solubilizing agent. The interaction between histidine and proteins in protein-based biopharmaceutical formulations, such as the Donnan effect during diafiltration of monoclonal antibody solutions and the degradation of polysorbates in histidine buffer, has also been discussed. As the first review of histidine in protein biopharmaceuticals, it helps to deepen our understanding of the opportunities and challenges associated with histidine as an excipient for protein-based biopharmaceutical formulations.
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Affiliation(s)
- Jia-Yi Lv
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Taizhou Institute of Zhejiang University, Taizhou, Zhejiang 317000, China; School of Pharmaceutical Sciences, Xiamen University, 4221 Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Rahul G Ingle
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Datta Meghe College of Pharmacy, Datta Meghe Institute of Higher Education & Research (Deemed to University), Sawangi, Wardha, India
| | - Hao Wu
- School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, China
| | - Cuihua Liu
- Bio-Thera Solutions, Ltd, Guangzhou, Guangdong 510530, China
| | - Wei-Jie Fang
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Taizhou Institute of Zhejiang University, Taizhou, Zhejiang 317000, China; Innovation Center of Translational Pharmacy, Jinhua Institute of Zhejiang University, Jinhua, 321000, China; Hangzhou Institute of Innovative Medicine, Zhejiang University, Hangzhou, 310016, China.
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4
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Manning MC, Holcomb RE, Payne RW, Stillahn JM, Connolly BD, Katayama DS, Liu H, Matsuura JE, Murphy BM, Henry CS, Crommelin DJA. Stability of Protein Pharmaceuticals: Recent Advances. Pharm Res 2024; 41:1301-1367. [PMID: 38937372 DOI: 10.1007/s11095-024-03726-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 06/03/2024] [Indexed: 06/29/2024]
Abstract
There have been significant advances in the formulation and stabilization of proteins in the liquid state over the past years since our previous review. Our mechanistic understanding of protein-excipient interactions has increased, allowing one to develop formulations in a more rational fashion. The field has moved towards more complex and challenging formulations, such as high concentration formulations to allow for subcutaneous administration and co-formulation. While much of the published work has focused on mAbs, the principles appear to apply to any therapeutic protein, although mAbs clearly have some distinctive features. In this review, we first discuss chemical degradation reactions. This is followed by a section on physical instability issues. Then, more specific topics are addressed: instability induced by interactions with interfaces, predictive methods for physical stability and interplay between chemical and physical instability. The final parts are devoted to discussions how all the above impacts (co-)formulation strategies, in particular for high protein concentration solutions.'
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Affiliation(s)
- Mark Cornell Manning
- Legacy BioDesign LLC, Johnstown, CO, USA.
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
| | - Ryan E Holcomb
- Legacy BioDesign LLC, Johnstown, CO, USA
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Robert W Payne
- Legacy BioDesign LLC, Johnstown, CO, USA
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Joshua M Stillahn
- Legacy BioDesign LLC, Johnstown, CO, USA
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | | | | | | | | | | | - Charles S Henry
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
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5
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Fischer P, Merkel OM, Siedler M, Huelsmeyer M. Development of a high throughput oxidation profiling strategy for monoclonal antibody products. Eur J Pharm Biopharm 2024; 199:114301. [PMID: 38677563 DOI: 10.1016/j.ejpb.2024.114301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 04/29/2024]
Abstract
Oxidation is one of the most common degradation pathways of biopharmaceutics, potentially leading to altered product stability, pharmacokinetics, reduced biological activity and/or an increased immunogenicity. However, it is often insufficiently assessed in early development stages, leaving potential molecule liabilities undiscovered. Aim of the present work was the development of a high throughput oxidation profiling strategy, applicable throughout various stages of biopharmaceutical development. The study demonstrates that the combination of multiple stress assays, including peroxide-based, visible light, and metal-catalyzed oxidation (MCO), enables a comprehensive understanding of a mAb's oxidation susceptibility. The most effective parameters to evaluate oxidation in a high-throughput screening workflow are aggregation, tryptophan oxidation and changes in the hydrophobicity profile of the Fc and Fab subunit measured via Size Exclusion Chromatography, Intrinsic Tryptophan Fluorescence Emission spectroscopy and Reversed-Phase Chromatography subunit analysis, respectively. This oxidation profiling approach is valuable tool to systematically characterize the oxidation susceptibility under relevant conditions, time effective and with minimal sample consumption.
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Affiliation(s)
- Paulina Fischer
- AbbVie Deutschland GmbH & Co. KG, Drug Product Development, Knollstraße, Ludwigshafen am Rhein, Germany.
| | - Olivia M Merkel
- Ludwig-Maximilians-Universität München, Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Munich, Germany
| | - Michael Siedler
- AbbVie Deutschland GmbH & Co. KG, Drug Product Development, Knollstraße, Ludwigshafen am Rhein, Germany
| | - Martin Huelsmeyer
- AbbVie Deutschland GmbH & Co. KG, Drug Product Development, Knollstraße, Ludwigshafen am Rhein, Germany
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6
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Zhang Y, Wu Y, Schöneich C. Near UV Photodegradation Mechanisms of Amino Acid Excipients: Formation of the Carbon Dioxide Radical Anion from Aspartate and Fe(III). Mol Pharm 2024; 21:1233-1245. [PMID: 38350108 DOI: 10.1021/acs.molpharmaceut.3c00893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
Carbon dioxide radical anion (•CO2-) is a powerful reducing agent that can reduce protein disulfide bonds and convert molecular oxygen to superoxide. Therefore, the generation of •CO2- can be detrimental to pharmaceutical formulations. Iron is among the most prevalent impurities in formulations, where Fe(III) chelates of histidine (His) can produce •CO2- upon exposure to near-UV light (Zhang and Schöneich, Eur. J. Pharm. Biopharm. 2023, 190, 231-241). Here, we monitor by spin-trapping in combination with electron paramagnetic resonance spectroscopy and/or high-performance liquid chromatography-mass spectrometry analysis the photochemical formation of •CO2- for a series of common amino acid excipients, including arginine (Arg), methionine (Met), proline (Pro), glutamic acid (Glu), glycine (Gly), aspartic acid (Asp), and lysine (Lys). Our results indicate that in the presence of Fe(III), Asp, and Glu produce significant yields of •CO2- under photoirradiation with near-UV light. Notably, Asp demonstrates the highest efficiency of •CO2- generation compared with that of the other amino acid excipients. Stable isotope labeling indicates that •CO2- exclusively originates from the α-carboxyl group of Asp. Mechanistic studies reveal two possible pathways for •CO2- formation, which involve either a β-carboxyl radical or an amino radical cation intermediate.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Yaqi Wu
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
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7
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Lou H, Zhang Y, Kuczera K, Hageman MJ, Schöneich C. Molecular Dynamics Simulation of an Iron(III) Binding Site on the Fc Domain of IgG1 Relevant for Visible Light-Induced Protein Fragmentation. Mol Pharm 2024; 21:501-512. [PMID: 38128475 DOI: 10.1021/acs.molpharmaceut.3c00612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Molecular dynamics simulations were employed to investigate the interaction between Fe(III) and an iron-binding site composed of THR259, ASP252, and GLU261 on the Fc domain of an IgG1. The goal was to provide microscopic mechanistic information for the photochemical, iron-dependent site-specific oxidative fragmentation of IgG1 at THR259 reported in our previous paper. The distance between Fe(III) and residues of interest as well as the binding pocket size was examined for both protonated and deprotonated THR259. The Fe(III) binding free energy (ΔG) was estimated by using an umbrella sampling approach. The pKa shift of the THR259 hydroxyl group caused by the presence of nearby Fe(III) was estimated based on a thermodynamic cycle. The simulation results show that Fe(III) resides inside the proposed binding pocket and profoundly changes the pocket configuration. The ΔG values indicate that the pocket possesses a strong binding affinity for Fe(III). Furthermore, Fe(III) profoundly lowers the pKa value of the THR259 hydroxyl group by 5.4 pKa units.
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Affiliation(s)
- Hao Lou
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
- Biopharmaceutical Innovation and Optimization Center, University of Kansas, Lawrence, Kansas 66047, United States
| | - Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
| | - Krzysztof Kuczera
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States
| | - Michael J Hageman
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
- Biopharmaceutical Innovation and Optimization Center, University of Kansas, Lawrence, Kansas 66047, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
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8
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Zhang Y, Ballesteros ME, Schöneich C. Photo-induced site-specific oxidative fragmentation of IgG1 mediated by iron(III)-containing histidine buffer: Mechanistic studies and excipient effects. Eur J Pharm Biopharm 2023; 190:121-130. [PMID: 37482364 DOI: 10.1016/j.ejpb.2023.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/14/2023] [Accepted: 07/21/2023] [Indexed: 07/25/2023]
Abstract
Fragmentation may compromise the clinical efficacy and safety profile of monoclonal antibodies (mAbs). We recently reported that Fe(III)-containing histidine (His) buffer mediates site-specific mAb fragmentation within the Fc domain when exposed to visible light (Y. Zhang and C. Schöneich, Mol. Pharm. 2023, 20, 650-662). Here, we show that this fragmentation proceeds even more efficiently under near-UV light. Several formulation strategies were applied in an attempt to reduce the photo-induced fragmentation. In solution formulations, the fragmentation can be mitigated by reducing the concentration of His buffer, adding Fe(III)-chelating agents, and replacing His with other amino acids. Fragmentation can be almost completely inhibited by formulating the protein in the lyophilized state. Mechanistically, His plays a critical role in the fragmentation process, likely due to its affinity for Fe(II), driving a photo-redox reaction towards product formation.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
| | | | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA.
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9
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Zhang Y, Schöneich C. Near UV light photo-degradation of histidine buffer: Mechanisms and role of Fe(III). Eur J Pharm Biopharm 2023; 190:231-241. [PMID: 37543156 DOI: 10.1016/j.ejpb.2023.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/01/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023]
Abstract
Pharmaceutical formulations are sensitive to light-induced degradation. Recent studies have attributed some of the light sensitivity to the presence of Fe(III), the most prevalent metal leachable from pharmaceutical containers. Histidine (His) can promote Fe(III) leaching from stainless steel, especially at elevated storage temperatures. Since there is the chance that combinations of His and Fe(III) are present in pharmaceutical formulations, we investigated the photo-degradation mechanisms of Fe(III)-containing His buffer during expsoure to near UV light. Our results indicate the formation of carbon dioxide radical anion (•CO2-), a powerful reductant, and other photoproducts such as aldehydes and His-derived radicals. The generation of •CO2- can be promoted by increasing concentrations of Fe(III) and inhibited by the addition of the Fe(III) chelator EDTA. Mechanistically, product formation can be rationalized by photo-induced ligand-to-metal-charge-transfer (LMCT), followed by a series of radical transformations of reaction intermediates.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA.
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10
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Schöneich C. Primary Processes of Free Radical Formation in Pharmaceutical Formulations of Therapeutic Proteins. Biomolecules 2023; 13:1142. [PMID: 37509177 PMCID: PMC10376966 DOI: 10.3390/biom13071142] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Oxidation represents a major pathway for the chemical degradation of pharmaceutical formulations. Few specific details are available on the mechanisms that trigger oxidation reactions in these formulations, specifically with respect to the formation of free radicals. Hence, these mechanisms must be formulated based on information on impurities and stress factors resulting from manufacturing, transportation and storage. In more detail, this article focusses on autoxidation, metal-catalyzed oxidation, photo-degradation and radicals generated from cavitation as a result of mechanical stress. Emphasis is placed on probable rather than theoretically possible pathways.
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Affiliation(s)
- Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
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11
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Sreenivasan S, Rathore AS. Combined Presence of Ferrous Ions and Hydrogen Peroxide in Normal Saline and In Vitro Models Induces Enhanced Aggregation of Therapeutic IgG due to Hydroxyl Radicals. Mol Pharm 2023. [PMID: 37189260 DOI: 10.1021/acs.molpharmaceut.3c00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Therapeutic monoclonal antibodies (mAb) are known to form aggregates and fragments upon exposure to hydrogen peroxide (H2O2) and ferrous ions (Fe2+). H2O2 and Fe2+ react to form hydroxyl radicals that are detrimental to protein structures. In this study, aggregation of mAb in the combined presence of Fe2+ and H2O2 was investigated in saline and physiologically relevant in vitro models. In the first case study, forced degradation of mAb in saline (a fluid used for administration of mAb) was carried out at 55 °C in the combined presence of 0.2 mM Fe2+ and 0.1% H2O2. The control and stressed samples were analyzed using an array of techniques including visual observation, size-exclusion chromatography (SEC), dynamic light scattering (DLS), microscopy, UV-vis, fluorescence, Fourier transform infrared spectroscopy, and cell-based toxicity assays. At the end of 1 h, samples having the combined presence of both Fe2+ and H2O2 exhibited more than 20% HMW (high molecular weight species), whereas samples having only Fe2+, H2O2, or neither resulted in less than 3% HMW. Aggregate-rich samples also exhibited altered protein structures and hydrophobicity. Aggregation increased upon increasing the time, temperature, and concentration of Fe2+ and H2O2. Samples having both Fe2+ and H2O2 also showed higher cytotoxicity in red blood cells. Samples of mAb with chlorides of copper and cobalt with H2O2 also resulted in multifold degradation. The first case study showed enhanced aggregation of mAb in the combined presence of Fe2+ and H2O2 in saline. In the second case study, aggregation of mAb was investigated in artificially prepared extracellular saline and in vitro models such as macromolecule free fraction of serum and serum. In the presence of both Fe2+ and H2O2, %HMW was higher in extracellular saline compared to macromolecule free fraction of serum. Further, in vitro models having the combined presence of Fe2+ and H2O2 resulted in enhanced aggregation of mAb compared to models that had neither.
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Affiliation(s)
- Shravan Sreenivasan
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Anurag S Rathore
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
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