Get low with Honeybun: 15 microliter rapid viscosity measurements

Importance of the Topic

Biological therapeutics require reliable viscosity data to ensure efficient development, formulation stability, and patient-friendly subcutaneous administration. High viscosity can impede manufacturing steps such as filtration and filling and limit injectability.

Objectives and Study Overview

This application note introduces the Honeybun microvolume viscometer and rheometer, designed to deliver rapid and accurate viscosity measurements from low sample volumes. Performance was evaluated using medical grade viscosity standards, an 88% glycerol solution, and two monoclonal antibody formulations across multiple temperatures and sample volumes.

Instrumentation Used

• Honeybun viscometer and rheometer with capacity for up to 10 parallel channels
• Bun disposable consumables requiring 15 µL (low volume) or 35 µL (default) sample per channel
• Integrated temperature control ranging from 10 to 45 °C

Main Results and Discussion

• Viscosities of viscosity standards (1.2–10 cP) and an 88% glycerol solution measured in quadruplicate showed no significant difference between default and low volume modes.
• Accuracy was within 3% of target values in default mode with coefficients of variation (CV) ≤1.8%; low volume mode CVs were ≤4% with values within 5% of targets.
• Two monoclonal antibodies at 200 mg/mL were tested at 10, 25, and 40 °C; viscosity decreased with increasing temperature in both modes.
• Antibody differences: mAb1 showed lower viscosity than mAb2 under identical conditions, reflecting weaker protein–protein interactions.
• Subcutaneous injection threshold (~20 cP) was exceeded by mAb2 at 10 and 25 °C, highlighting the importance of early viscosity screening.

Benefits and Practical Applications

• High-throughput measurement of up to ten samples in under ten minutes accelerates screening workflows.
• Minimal sample consumption (15 µL) preserves valuable biologic material.
• No extensive cleaning or calibration required between runs reduces hands-on time.
• Temperature control allows assessment of viscosity under storage and physiological conditions.

Future Trends and Potential Applications

• Integration into automated formulation screening pipelines for biologics, vaccines, and viral vectors.
• Expansion to study protein–excipient interactions and stability profiling.
• Development of advanced data analytics for predicting formulation behavior.
• Adaptation for broader rheological measurements beyond simple viscosity.

Conclusion

Honeybun offers a fast, reliable, and low volume solution for viscosity assessment, enabling parallel analysis and robust temperature control without extensive maintenance. It supports streamlined biologic development by quickly identifying formulation challenges and guiding optimization.

References

1. Shire SJ. Strategies to address challenges of high-concentration subcutaneous monoclonal antibody formulations. Monoclon Antib Antib. 2015;139–152.
2. Cheng NS. Formula for the viscosity of a glycerol–water mixture. Ind Eng Chem Res. 2008;47(9):3285–3288.
3. Hong T, et al. Viscosity control of protein solutions by small solutes: a review. Curr Protein Pept Sci. 2017;19(8):746–758.
4. Berteau C, et al. Impact of viscosity, injection volume, and flow rate on subcutaneous injection tolerance. Med Devices (Auckl). 2015;8:473–484.