In-situ biophysical characterization of high-concentration protein formulations using wNMR.

High-concentration protein formulation is of paramount importance in patient-centric drug product development, but it also presents challenges due to the potential for enhanced aggregation and increased viscosity. The analysis of critical quality attributes often necessitates the transfer of samples from their primary containers together with sample dilution. Therefore, there is a demand for noninvasive, in situ biophysical methods to assess protein drug products directly in primary sterile containers, such as prefilled syringes, without dilution. In this study, we introduce a novel application of water proton nuclear magnetic resonance (wNMR) to evaluate the aggregation propensity of a high-concentration drug product, Dupixent® (dupilumab), under stress conditions. wNMR results demonstrate a concentration-dependent, reversible association of dupilumab in the commercial formulation, as well as irreversible aggregation when exposed to accelerated thermal stress, but gradually reversible aggregation when exposed to freeze and thaw cycles. Importantly, these results show a strong correlation with data obtained from established biophysical analytical tools widely used in the pharmaceutical industry. The application of wNMR represents a promising approach for in situ noninvasive analysis of high-concentration protein formulations directly in their primary containers, providing valuable insights for drug development and quality assessment.

Functional insights from a comparative study on the dynamics of Antigen85 proteins and MPT51 from Mycobacterium tuberculosis.

Antigen85 (Ag85) proteins of Mycobacterium tuberculosis are mycolyl transferases that aid in cell wall biosynthesis. MPT51 (Ag85D) is closely related to Ag85 proteins. We have performed a comparative molecular dynamics (MD) simulation study of Ag85 proteins (Ag85A, Ag85B, and Ag85C) and MPT51. We observe that helix α5, ß7-α9 loop, and N-terminal region of helix α9 of Ag85 proteins are mobile, suggestive of lid like movement over the active site. Further, in Ag85B, we observe the proposed scooting mode of the hydrophobic gating residue Phe232. Our simulations also show a similar scooting mode for Phe232 of Ag85A and Trp158 of Ag85C. We also found aromatic residue clusters at the ends of the hydrophobic channel of Ag85 proteins, which may have functional significance. Although MPT51 lacks the tunnel, it has the aromatic clusters. The aromatic cluster region has the ability to bind trehalose. From an immunoinformatics study, a promiscuous linear epitope was identified in MPT51 which could be useful in subunit vaccine studies. Recent studies have shown that a mycobacterial protein HupB, interacts with Ag85 proteins and has a regulatory role in cell wall biogenesis, with implications in growth rate and latency. We performed molecular docking studies of HupB protein with Ag85 proteins and predicted potential sites of interaction in Ag85 proteins. The insights gained through the current study can potentially pave way for newer therapeutic interventions. Graphical Abstract Dynamics of antigen85 proteins and MPT51 from Mycobacterium tuberculosis.