Sail through formulation screening on Uncle and Honeybun

Significance of the topic

The stability and viscosity of monoclonal antibodies and other biologics are critical parameters throughout discovery, development and manufacturing. High-concentration formulations often exhibit elevated viscosity and aggregation tendencies that can compromise manufacturability, safety and patient delivery. Early identification of optimal excipients and formulation conditions using minimal sample volumes accelerates developability assessments and reduces timelines for bringing new therapies to clinic.

Objectives and Study Overview

This application note evaluates the combined use of the Uncle all-in-one stability platform and the Honeybun microvolume viscometer for high-throughput formulation screening of four monoclonal antibodies. The goals were to measure conformational stability (Tm), aggregation onset (Tagg), particle size distributions by DLS, and solution viscosity across multiple formulations and concentrations, and to identify the most stabilizing excipients.

Methodology and Instrumentation

Four antibodies (mAb1, mAb2, adalimumab, trastuzumab) were buffer-exchanged into 10 mM histidine, pH 6, with 0.001% PS80 and spiked with either 0.9% NaCl, 80 mg/mL sucrose, 10 mg/mL arginine or both sucrose and arginine. Samples were tested at 1, 10 and 100 mg/mL.

Instrumentation:

• Uncle stability analyzer: measures intrinsic fluorescence, static light scattering (SLS) and dynamic light scattering (DLS) on 9 µL sealed samples over 15–95 °C to derive Tm, Tagg and hydrodynamic diameters.
• Honeybun microviscometer: determines viscosity of 15–35 µL samples across 0.5–150 cP in parallel (up to 10 samples) within minutes.

Main Results and Discussion

Tm and Tagg screening showed that sucrose consistently raised the melting temperature and delayed aggregation of mAb1 and trastuzumab at all concentrations compared to NaCl. The combination of sucrose and arginine provided the greatest stabilization for mAb2 and adalimumab, particularly at 100 mg/mL, while NaCl alone had a destabilizing effect on most antibodies.

DLS data confirmed that sucrose limited the formation of large aggregates upon heating. Formulations containing arginine or NaCl exhibited broader size distributions and higher SLS signals, indicating more extensive aggregation.

Viscosity measurements at 100 mg/mL revealed that sucrose-only formulations had higher viscosities than NaCl controls. Arginine reduced viscosity in mAb2 but increased it in mAb1, illustrating that viscosity-modulating effects of excipients depend on the specific protein.

Benefits and Practical Applications

The integration of Uncle and Honeybun enables rapid, low-volume assessment of multiple critical quality attributes from the same sample set. This approach streamlines early formulation screening, supports selection of subcutaneous dosing concentrations, and helps mitigate risks related to protein stability, aggregation and injectability using minimal material.

Future Trends and Potential Applications

• Incorporation of machine learning models to predict excipient performance based on physicochemical properties.
• Expansion to complex biologics such as gene-therapy vectors and multi-specific antibodies.
• Automation of high-throughput screening workflows for combinatorial excipient libraries.
• Integration with real-time analytics and continuous manufacturing platforms.

Conclusion

The combined use of full-spectrum fluorescence, light scattering and microvolume viscosity measurement provides a comprehensive, efficient route to optimize biologic formulations. These high-throughput, low-sample-consumption techniques accelerate developability assessments and support informed decision-making throughout the drug development pipeline.

References

• Jarasch A, et al. Developability assessment during the selection of novel therapeutic antibodies. Journal of Pharmaceutical Sciences. 2015;104(6):1885–1898.
• Wang W, et al. Antibody Structure, Instability, and Formulation. Journal of Pharmaceutical Sciences. 2007;96(1):1–26.
• Kamerzell TJ, et al. Protein-excipient interactions: Mechanisms and biophysical characterization applied to protein formulation development. Advanced Drug Delivery Reviews. 2011;63(13):1118–1159.
• Berteau C, et al. Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance. Medical Devices (Auckland, N.Z.). 2015;8:473–484.
• Hong T, et al. Viscosity Control of Protein Solution by Small Solutes: A Review. Current Protein & Peptide Science. 2017;19(8):746–758.