Abstract
N49P9.6-FR-LS and PGT121 are promising antibodies with significant therapeutic potential against HIV infection, but they are prone to precipitation at high concentrations. This study evaluates the influence of six excipients—L-arginine, L-alanine, sucrose, trehalose, methionine, and glutamate—on the biophysical stability of antibodies. We employed a comprehensive approach, combining computational mAb-excipient interaction analysis via the site-identification by ligand competitive saturation (SILCS) method with extensive experimental characterization. Our experimental matrix included viscosity measurements across temperature gradients, particle size distribution, zeta potential, pH value, and solution appearance, alongside a short-term stability study at 30°C and 65% relative humidity, with assessments at t0 (initial), t1 (14 days), and t2 (28 days). Results indicated that sucrose, arginine, alanine, and trehalose provided varying degrees of stabilization for both antibodies. Conversely, glutamate destabilized PGT121 but stabilized N49P9.6-FR-LS, while methionine had a negative effect on N49P9.6-FR-LS but a positive one on PGT121. SILCS-Biologics analysis suggested that stabilization by these excipients is linked to their ability to occupy regions involved in self-protein interactions. Debye–Hückel–Henry charge calculations further indicated that neutral excipients like sucrose and trehalose could alter mAb charges by affecting buffer binding, influencing aggregation propensity. These findings offer valuable insights for optimizing antibody formulations, ensuring enhanced stability and therapeutic efficacy for HIV treatment.
Supplementary materials
Title
Supporting material pdf
Description
Size exclusion chromatography showing mAb purity and summary of information in the supplementary spreadsheet: hiv_mab_silcs_metrics_sm.xlsx
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Title
Supplemental material spreadsheet
Description
Select SILCS-Biologics metrics and their correlations with experimental data. The SILCS-Biologics metrics indicate the energetic favorability of the excipients interacting with the mAbs, the ability of the excipients to cover the surface of the mAbs, and/or the proximity of the bound excipients to regions of the mAbs involved in protein-protein interaction (PPI), hydrophobic patches, charged patches, or potentially stabilizing intramolecular interactions. The experimental data used in the correlations are tabulated, see spreadsheet tab “Experimental Data” and are also provided in Tables 3, 6, 7, and 10 of the main text.
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