The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
T B Ng - One of the best experts on this subject based on the ideXlab platform.
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Purification and characterization of α- and β-benincasins, Arginine/Glutamate-rich peptides with translation-inhibiting activity from wax gourd seeds
Peptides, 2020Co-Authors: T B Ng, A. ParkashAbstract:Abstract Two peptides, with a molecular mass of about 11 kDa and an N-terminal sequence abundant in Arginine and glutamine residues, were isolated from wax gourd seeds. The isolation protocol included affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono-S and gel filtration on Superdex 75. The peptides, designated α- and β-benincasins, inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC 50 of 20 and 320 pM, respectively. α-Benincasin exhibited weak antifungal activity toward Coprinus comatus and Physalospora piricola but not toward Mycosphaerella arachidicola .
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isolation of cucurmoschin a novel antifungal peptide abundant in Arginine Glutamate and glycine residues from black pumpkin seeds
Peptides, 2003Co-Authors: Hexiang Wang, T B NgAbstract:Abstract A novel antifungal peptide, with a molecular mass of 8 kDa in sodium dodecyl sulfate–polyacrylamide gel electrophoresis and in gel filtration on Superdex 75 and designated cucurmoschin, was isolated from the seeds of the black pumpkin. The peptide was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel. Cucurmoschin inhibited mycelial growth in the fungi Botrytis cinerea, Fusarium oxysporum and Mycosphaerella oxysporum. It inhibited translation in a cell-free rabbit reticulocyte lysate system with an IC50 of 1.2 μM. The N-terminal sequence of cucurmoschin was rich in Arginine, Glutamate and glycine residues.
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purification and characterization of α and β benincasins Arginine Glutamate rich peptides with translation inhibiting activity from wax gourd seeds
Peptides, 2003Co-Authors: T B Ng, A. ParkashAbstract:Abstract Two peptides, with a molecular mass of about 11 kDa and an N-terminal sequence abundant in Arginine and glutamine residues, were isolated from wax gourd seeds. The isolation protocol included affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono-S and gel filtration on Superdex 75. The peptides, designated α- and β-benincasins, inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC 50 of 20 and 320 pM, respectively. α-Benincasin exhibited weak antifungal activity toward Coprinus comatus and Physalospora piricola but not toward Mycosphaerella arachidicola .
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purification and characterization of moschins Arginine Glutamate rich proteins with translation inhibiting activity from brown pumpkin cucurbita moschata seeds
Protein Expression and Purification, 2002Co-Authors: T B Ng, A. ParkashAbstract:Abstract From fresh brown pumpkin seeds, two proteins with a molecular mass of 12 kDa and an N-terminal sequence rich in Arginine and Glutamate residues were obtained. The protein designated α-moschin closely resembled the fruitfly programmed-cell death gene product and the protein designated β-moschin demonstrated striking similarity to prepro 2S albumin in N-terminal sequence. α- and β-moschins inhibited translation in the rabbit reticulocyte lysate system with an IC50 of 17 μM and 300 nM, respectively.
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Isolation and characterization of luffacylin, a ribosome inactivating peptide with anti-fungal activity from sponge gourd (Luffa cylindrica) seeds
Peptides, 2002Co-Authors: A. Parkash, T B NgAbstract:Abstract A purification scheme involving ion exchange chromatography on DEAE–cellulose, affinity chromatography on Affi-gel blue gel, and ion exchange chromatography on CM–Sepharose and Mono S was employed to isolate a peptide with a molecular weight of 7.8 kDa from sponge gourd seeds. The peptide, which was designated luffacylin, exhibited an N-terminal sequence with pronounced resemblance to that of the 6.5 kDa Arginine–Glutamate rich polypeptide previously isolated from sponge gourd seeds. Luffacylin inhibited translation in a rabbit reticulocyte lysate system with an ic 50 of 140 pM and reacted positively in the N -glycosidase assay for ribosome inactivating proteins. Luffacylin exerted anti-fungal activity against Mycosphaerella arachidicola and Fusarium oxysporum .
Alexander P Golovanov - One of the best experts on this subject based on the ideXlab platform.
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Orthogonal Techniques to Study the Effect of pH, Sucrose, and Arginine Salts on Monoclonal Antibody Physical Stability and Aggregation During Long-Term Storage
Journal of Pharmaceutical Sciences, 2019Co-Authors: Hristo Svilenov, Alexander P Golovanov, Alina Kulakova, Matja Zalar, Pernille Harris, Gerhard WinterAbstract:Abstract Understanding the effects of additives on therapeutic protein stability is of paramount importance for obtaining stable formulations. In this work, we apply several high- and medium-throughput methods to study the physical stability of a model monoclonal antibody at pH 5.0 and 6.5 in the presence of sucrose, Arginine hydrochloride and Arginine Glutamate. In low ionic strength buffer, the addition of salts reduces the antibody colloidal and thermal stability, attributed to screening of electrostatic interactions. The presence of Glutamate ion in the Arginine salt partially reduces the damaging effect of ionic strength increase. The addition of 280 mM sucrose shifts the thermal protein unfolding to a higher temperature. Arginine salts in the used concentration reduce the relative monomer yield after refolding from urea, while sucrose has a favorable effect on antibody refolding. In addition, we show 12-month long-term stability data and observe correlations between thermal protein stability, relative monomer yield after refolding and monomer loss during storage. The monomer loss during storage is related to protein aggregation and formation of subvisible particles in some of the formulations. This study shows that the effect of commonly used additives on the long-term antibody physical stability can be predicted using orthogonal biophysical measurements.
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19F Dark-State Exchange Saturation Transfer NMR Reveals Reversible Formation of Protein-Specific Large Clusters in High-Concentration Protein Mixtures
Analytical Chemistry, 2019Co-Authors: John Edwards, Christopher F Van Der Walle, Jack E. Bramham, Adrian Podmore, Steven M. Bishop, Alexander P GolovanovAbstract:Proteins frequently exist as high-concentration mixtures, both in biological environments and increasingly in biopharmaceutical co-formulations. Such crowded conditions promote protein–protein interactions, potentially leading to formation of protein clusters, aggregation, and phase separation. Characterizing these interactions and processes in situ in high-concentration mixtures is challenging due to the complexity and heterogeneity of such systems. Here we demonstrate the application of the dark-state exchange saturation transfer (DEST) NMR technique to a mixture of two differentially 19F-labeled 145 kDa monoclonal antibodies (mAbs) to assess reversible temperature-dependent formation of small and large protein-specific clusters at concentrations up to 400 mg/mL. 19F DEST allowed quantitative protein-specific characterization of the cluster populations and sizes for both mAbs in the mixture under a range of conditions. Additives such as Arginine Glutamate and NaCl also had protein-specific effects on th...
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Investigating Liquid–Liquid Phase Separation of a Monoclonal Antibody Using Solution-State NMR Spectroscopy: Effect of Arg·Glu and Arg·HCl
Molecular Pharmaceutics, 2017Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Rebecca J Dearman, Jack E. Bramham, Alexander P GolovanovAbstract:Liquid–liquid phase separation (LLPS) of monoclonal antibody (mAb) formulations involves spontaneous separation into dense (protein-rich) and diluted (protein-lean) phases and should be avoided in the final drug product. Understanding the factors leading to LLPS and ways to predict and prevent it would therefore be highly beneficial. Here we describe the link between LLPS behavior of an IgG1 mAb (mAb5), its solubility, and parameters extracted using 1H NMR spectroscopy, for various formulations. We show that the formulations demonstrating least LLPS lead to the largest mAb5 NMR signal intensities. In the formulations exhibiting the highest propensity to phase-separate the mAb NMR signal intensities are the lowest, even at higher temperatures without visible phase separation, suggesting a high degree of self-association prior to distinct phase separation. Addition of Arginine Glutamate prevented LLPS and led to a significant increase in the observed mAb signal intensity, whereas the effect of Arginine hydr...
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characterizing monoclonal antibody formulations in Arginine Glutamate solutions using 1h nmr spectroscopy
mAbs, 2016Co-Authors: Priscilla Kheddo, Matthew J Cliff, Shahid Uddin, Christopher F Van Der Walle, Alexander P GolovanovAbstract:ABSTRACTAssessing how excipients affect the self-association of monoclonal antibodies (mAbs) requires informative and direct in situ measurements for highly concentrated solutions, without sample dilution or perturbation. This study explores the application of solution nuclear magnetic resonance (NMR) spectroscopy for characterization of typical mAb behavior in formulations containing Arginine Glutamate. The data show that the analysis of signal intensities in 1D 1H NMR spectra, when compensated for changes in buffer viscosity, is invaluable for identifying conditions where protein-protein interactions are minimized. NMR-derived molecular translational diffusion rates for concentrated solutions are less useful than transverse relaxation rates as parameters defining optimal formulation. Furthermore, NMR reports on the solution viscosity and mAb aggregation during accelerated stability study assessment, generating data consistent with that acquired by size-exclusion chromatography. The methodology developed...
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the effects of Arginine Glutamate a promising excipient for protein formulation on cell viability comparisons with nacl
Toxicology in Vitro, 2016Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Alexander P Golovanov, Kieran T Mellody, Rebecca J DearmanAbstract:The effects of an equimolar mixture of l-Arginine and l-Glutamate (Arg·Glu) on cell viability and cellular stress using in vitro cell culture systems are examined with reference to NaCl, in the context of monoclonal antibody formulation. Cells relevant to subcutaneous administration were selected: the human monocyte cell line THP-1, grown as a single cell suspension, and adherent human primary fibroblasts. For THP-1 cells, the mechanism of cell death caused by relatively high salt concentrations was investigated and effects on cell activation/stress assessed as a function of changes in membrane marker and cytokine (interleukin-8) expression. These studies demonstrated that Arg·Glu does not have any further detrimental effects on THP-1 viability in comparison to NaCl at equivalent osmolalities, and that both salts at higher concentrations cause cell death by apoptosis; there was no significant effect on measures of THP-1 cellular stress/activation. For adherent fibroblasts, both salts caused significant toxicity at ~ 400 mOsm/kg, although Arg·Glu caused a more precipitous subsequent decline in viability than did NaCl. These data indicate that Arg·Glu is of equivalent toxicity to NaCl and that the mechanism of toxicity is such that cell death is unlikely to trigger inflammation upon subcutaneous injection in vivo.
Priscilla Kheddo - One of the best experts on this subject based on the ideXlab platform.
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Investigating Liquid–Liquid Phase Separation of a Monoclonal Antibody Using Solution-State NMR Spectroscopy: Effect of Arg·Glu and Arg·HCl
Molecular Pharmaceutics, 2017Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Rebecca J Dearman, Jack E. Bramham, Alexander P GolovanovAbstract:Liquid–liquid phase separation (LLPS) of monoclonal antibody (mAb) formulations involves spontaneous separation into dense (protein-rich) and diluted (protein-lean) phases and should be avoided in the final drug product. Understanding the factors leading to LLPS and ways to predict and prevent it would therefore be highly beneficial. Here we describe the link between LLPS behavior of an IgG1 mAb (mAb5), its solubility, and parameters extracted using 1H NMR spectroscopy, for various formulations. We show that the formulations demonstrating least LLPS lead to the largest mAb5 NMR signal intensities. In the formulations exhibiting the highest propensity to phase-separate the mAb NMR signal intensities are the lowest, even at higher temperatures without visible phase separation, suggesting a high degree of self-association prior to distinct phase separation. Addition of Arginine Glutamate prevented LLPS and led to a significant increase in the observed mAb signal intensity, whereas the effect of Arginine hydr...
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characterizing monoclonal antibody formulations in Arginine Glutamate solutions using 1h nmr spectroscopy
mAbs, 2016Co-Authors: Priscilla Kheddo, Matthew J Cliff, Shahid Uddin, Christopher F Van Der Walle, Alexander P GolovanovAbstract:ABSTRACTAssessing how excipients affect the self-association of monoclonal antibodies (mAbs) requires informative and direct in situ measurements for highly concentrated solutions, without sample dilution or perturbation. This study explores the application of solution nuclear magnetic resonance (NMR) spectroscopy for characterization of typical mAb behavior in formulations containing Arginine Glutamate. The data show that the analysis of signal intensities in 1D 1H NMR spectra, when compensated for changes in buffer viscosity, is invaluable for identifying conditions where protein-protein interactions are minimized. NMR-derived molecular translational diffusion rates for concentrated solutions are less useful than transverse relaxation rates as parameters defining optimal formulation. Furthermore, NMR reports on the solution viscosity and mAb aggregation during accelerated stability study assessment, generating data consistent with that acquired by size-exclusion chromatography. The methodology developed...
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the effects of Arginine Glutamate a promising excipient for protein formulation on cell viability comparisons with nacl
Toxicology in Vitro, 2016Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Alexander P Golovanov, Kieran T Mellody, Rebecca J DearmanAbstract:The effects of an equimolar mixture of l-Arginine and l-Glutamate (Arg·Glu) on cell viability and cellular stress using in vitro cell culture systems are examined with reference to NaCl, in the context of monoclonal antibody formulation. Cells relevant to subcutaneous administration were selected: the human monocyte cell line THP-1, grown as a single cell suspension, and adherent human primary fibroblasts. For THP-1 cells, the mechanism of cell death caused by relatively high salt concentrations was investigated and effects on cell activation/stress assessed as a function of changes in membrane marker and cytokine (interleukin-8) expression. These studies demonstrated that Arg·Glu does not have any further detrimental effects on THP-1 viability in comparison to NaCl at equivalent osmolalities, and that both salts at higher concentrations cause cell death by apoptosis; there was no significant effect on measures of THP-1 cellular stress/activation. For adherent fibroblasts, both salts caused significant toxicity at ~ 400 mOsm/kg, although Arg·Glu caused a more precipitous subsequent decline in viability than did NaCl. These data indicate that Arg·Glu is of equivalent toxicity to NaCl and that the mechanism of toxicity is such that cell death is unlikely to trigger inflammation upon subcutaneous injection in vivo.
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the effect of Arginine Glutamate on the stability of monoclonal antibodies in solution
International Journal of Pharmaceutics, 2014Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Malgorzata B Tracka, Jonathan Armer, Rebecca J Dearman, Alexander P GolovanovAbstract:Finding excipients which mitigate protein self-association and aggregation is an important task during formulation. Here, the effect of an equimolar mixture of l-Arg and l-Glu (Arg·Glu) on colloidal and conformational stability of four monoclonal antibodies (mAb1–mAb4) at different pH is explored, with the temperatures of the on-set of aggregation (Tagg) and unfolding (Tm1) measured by static light scattering and intrinsic fluorescence, respectively. Arg·Glu increased the Tagg of all four mAbs in concentration-dependent manner, especially as pH increased to neutral. Arg·Glu also increased Tm1 of the least thermally stable mAb3, but without similar direct effect on the Tm1 of other mAbs. Raising pH itself from 5 to 7 increased Tm1 for all four mAbs. Selected mAb formulations were assessed under accelerated stability conditions for the monomer fraction remaining in solution after storage. The aggregation of mAb3 was suppressed to a greater extent by Arg·Glu than by Arg·HCl. Furthermore, Arg·Glu suppressed the aggregation of mAb1 at neutral pH such that the fraction monomer was near to that at the more typical formulation pH of 5.5. We conclude that Arg·Glu can suppress mAb aggregation with increasing temperature/pH and, importantly, under accelerated stability conditions at weakly acidic to neutral pH.
A. Parkash - One of the best experts on this subject based on the ideXlab platform.
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Purification and characterization of α- and β-benincasins, Arginine/Glutamate-rich peptides with translation-inhibiting activity from wax gourd seeds
Peptides, 2020Co-Authors: T B Ng, A. ParkashAbstract:Abstract Two peptides, with a molecular mass of about 11 kDa and an N-terminal sequence abundant in Arginine and glutamine residues, were isolated from wax gourd seeds. The isolation protocol included affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono-S and gel filtration on Superdex 75. The peptides, designated α- and β-benincasins, inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC 50 of 20 and 320 pM, respectively. α-Benincasin exhibited weak antifungal activity toward Coprinus comatus and Physalospora piricola but not toward Mycosphaerella arachidicola .
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purification and characterization of α and β benincasins Arginine Glutamate rich peptides with translation inhibiting activity from wax gourd seeds
Peptides, 2003Co-Authors: T B Ng, A. ParkashAbstract:Abstract Two peptides, with a molecular mass of about 11 kDa and an N-terminal sequence abundant in Arginine and glutamine residues, were isolated from wax gourd seeds. The isolation protocol included affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono-S and gel filtration on Superdex 75. The peptides, designated α- and β-benincasins, inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC 50 of 20 and 320 pM, respectively. α-Benincasin exhibited weak antifungal activity toward Coprinus comatus and Physalospora piricola but not toward Mycosphaerella arachidicola .
-
purification and characterization of moschins Arginine Glutamate rich proteins with translation inhibiting activity from brown pumpkin cucurbita moschata seeds
Protein Expression and Purification, 2002Co-Authors: T B Ng, A. ParkashAbstract:Abstract From fresh brown pumpkin seeds, two proteins with a molecular mass of 12 kDa and an N-terminal sequence rich in Arginine and Glutamate residues were obtained. The protein designated α-moschin closely resembled the fruitfly programmed-cell death gene product and the protein designated β-moschin demonstrated striking similarity to prepro 2S albumin in N-terminal sequence. α- and β-moschins inhibited translation in the rabbit reticulocyte lysate system with an IC50 of 17 μM and 300 nM, respectively.
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Isolation and characterization of luffacylin, a ribosome inactivating peptide with anti-fungal activity from sponge gourd (Luffa cylindrica) seeds
Peptides, 2002Co-Authors: A. Parkash, T B NgAbstract:Abstract A purification scheme involving ion exchange chromatography on DEAE–cellulose, affinity chromatography on Affi-gel blue gel, and ion exchange chromatography on CM–Sepharose and Mono S was employed to isolate a peptide with a molecular weight of 7.8 kDa from sponge gourd seeds. The peptide, which was designated luffacylin, exhibited an N-terminal sequence with pronounced resemblance to that of the 6.5 kDa Arginine–Glutamate rich polypeptide previously isolated from sponge gourd seeds. Luffacylin inhibited translation in a rabbit reticulocyte lysate system with an ic 50 of 140 pM and reacted positively in the N -glycosidase assay for ribosome inactivating proteins. Luffacylin exerted anti-fungal activity against Mycosphaerella arachidicola and Fusarium oxysporum .
Christopher F Van Der Walle - One of the best experts on this subject based on the ideXlab platform.
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19F Dark-State Exchange Saturation Transfer NMR Reveals Reversible Formation of Protein-Specific Large Clusters in High-Concentration Protein Mixtures
Analytical Chemistry, 2019Co-Authors: John Edwards, Christopher F Van Der Walle, Jack E. Bramham, Adrian Podmore, Steven M. Bishop, Alexander P GolovanovAbstract:Proteins frequently exist as high-concentration mixtures, both in biological environments and increasingly in biopharmaceutical co-formulations. Such crowded conditions promote protein–protein interactions, potentially leading to formation of protein clusters, aggregation, and phase separation. Characterizing these interactions and processes in situ in high-concentration mixtures is challenging due to the complexity and heterogeneity of such systems. Here we demonstrate the application of the dark-state exchange saturation transfer (DEST) NMR technique to a mixture of two differentially 19F-labeled 145 kDa monoclonal antibodies (mAbs) to assess reversible temperature-dependent formation of small and large protein-specific clusters at concentrations up to 400 mg/mL. 19F DEST allowed quantitative protein-specific characterization of the cluster populations and sizes for both mAbs in the mixture under a range of conditions. Additives such as Arginine Glutamate and NaCl also had protein-specific effects on th...
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Investigating Liquid–Liquid Phase Separation of a Monoclonal Antibody Using Solution-State NMR Spectroscopy: Effect of Arg·Glu and Arg·HCl
Molecular Pharmaceutics, 2017Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Rebecca J Dearman, Jack E. Bramham, Alexander P GolovanovAbstract:Liquid–liquid phase separation (LLPS) of monoclonal antibody (mAb) formulations involves spontaneous separation into dense (protein-rich) and diluted (protein-lean) phases and should be avoided in the final drug product. Understanding the factors leading to LLPS and ways to predict and prevent it would therefore be highly beneficial. Here we describe the link between LLPS behavior of an IgG1 mAb (mAb5), its solubility, and parameters extracted using 1H NMR spectroscopy, for various formulations. We show that the formulations demonstrating least LLPS lead to the largest mAb5 NMR signal intensities. In the formulations exhibiting the highest propensity to phase-separate the mAb NMR signal intensities are the lowest, even at higher temperatures without visible phase separation, suggesting a high degree of self-association prior to distinct phase separation. Addition of Arginine Glutamate prevented LLPS and led to a significant increase in the observed mAb signal intensity, whereas the effect of Arginine hydr...
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characterizing monoclonal antibody formulations in Arginine Glutamate solutions using 1h nmr spectroscopy
mAbs, 2016Co-Authors: Priscilla Kheddo, Matthew J Cliff, Shahid Uddin, Christopher F Van Der Walle, Alexander P GolovanovAbstract:ABSTRACTAssessing how excipients affect the self-association of monoclonal antibodies (mAbs) requires informative and direct in situ measurements for highly concentrated solutions, without sample dilution or perturbation. This study explores the application of solution nuclear magnetic resonance (NMR) spectroscopy for characterization of typical mAb behavior in formulations containing Arginine Glutamate. The data show that the analysis of signal intensities in 1D 1H NMR spectra, when compensated for changes in buffer viscosity, is invaluable for identifying conditions where protein-protein interactions are minimized. NMR-derived molecular translational diffusion rates for concentrated solutions are less useful than transverse relaxation rates as parameters defining optimal formulation. Furthermore, NMR reports on the solution viscosity and mAb aggregation during accelerated stability study assessment, generating data consistent with that acquired by size-exclusion chromatography. The methodology developed...
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the effects of Arginine Glutamate a promising excipient for protein formulation on cell viability comparisons with nacl
Toxicology in Vitro, 2016Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Alexander P Golovanov, Kieran T Mellody, Rebecca J DearmanAbstract:The effects of an equimolar mixture of l-Arginine and l-Glutamate (Arg·Glu) on cell viability and cellular stress using in vitro cell culture systems are examined with reference to NaCl, in the context of monoclonal antibody formulation. Cells relevant to subcutaneous administration were selected: the human monocyte cell line THP-1, grown as a single cell suspension, and adherent human primary fibroblasts. For THP-1 cells, the mechanism of cell death caused by relatively high salt concentrations was investigated and effects on cell activation/stress assessed as a function of changes in membrane marker and cytokine (interleukin-8) expression. These studies demonstrated that Arg·Glu does not have any further detrimental effects on THP-1 viability in comparison to NaCl at equivalent osmolalities, and that both salts at higher concentrations cause cell death by apoptosis; there was no significant effect on measures of THP-1 cellular stress/activation. For adherent fibroblasts, both salts caused significant toxicity at ~ 400 mOsm/kg, although Arg·Glu caused a more precipitous subsequent decline in viability than did NaCl. These data indicate that Arg·Glu is of equivalent toxicity to NaCl and that the mechanism of toxicity is such that cell death is unlikely to trigger inflammation upon subcutaneous injection in vivo.
-
the effect of Arginine Glutamate on the stability of monoclonal antibodies in solution
International Journal of Pharmaceutics, 2014Co-Authors: Priscilla Kheddo, Shahid Uddin, Christopher F Van Der Walle, Malgorzata B Tracka, Jonathan Armer, Rebecca J Dearman, Alexander P GolovanovAbstract:Finding excipients which mitigate protein self-association and aggregation is an important task during formulation. Here, the effect of an equimolar mixture of l-Arg and l-Glu (Arg·Glu) on colloidal and conformational stability of four monoclonal antibodies (mAb1–mAb4) at different pH is explored, with the temperatures of the on-set of aggregation (Tagg) and unfolding (Tm1) measured by static light scattering and intrinsic fluorescence, respectively. Arg·Glu increased the Tagg of all four mAbs in concentration-dependent manner, especially as pH increased to neutral. Arg·Glu also increased Tm1 of the least thermally stable mAb3, but without similar direct effect on the Tm1 of other mAbs. Raising pH itself from 5 to 7 increased Tm1 for all four mAbs. Selected mAb formulations were assessed under accelerated stability conditions for the monomer fraction remaining in solution after storage. The aggregation of mAb3 was suppressed to a greater extent by Arg·Glu than by Arg·HCl. Furthermore, Arg·Glu suppressed the aggregation of mAb1 at neutral pH such that the fraction monomer was near to that at the more typical formulation pH of 5.5. We conclude that Arg·Glu can suppress mAb aggregation with increasing temperature/pH and, importantly, under accelerated stability conditions at weakly acidic to neutral pH.
