Bun solvent & surfactant compatibility

Importance of the Topic

The precise measurement of viscosity in aqueous formulations containing proteins, antibodies and vaccines is critical for formulation development, quality control and process optimization. The Bun microfluidic consumable, used with the Honeybun viscometer, offers a rapid and low-volume solution for such analyses, provided its chemical compatibility with solvents and surfactants is understood.

Objectives and Overview of the Study

This Technical Note evaluates the compatibility limits of various solvents and surfactants in aqueous media with the Bun microfluidic channel and examines the chemical resistance of the Bun material, cyclic olefin copolymer (COC), to a range of reagents.

Methodology and Instrumentation

Compatibility tests were conducted at 20°C by exposing the microfluidic channels to increasing concentrations of solvents and surfactants, observing self-loading behavior and potential contamination. Material resistance of COC was assessed by measuring weight changes after immersion in different chemicals, with thresholds set at less than 0.5 percent weight loss or less than 3 percent weight gain for compatibility.

Instrumentation Used

• Bun microfluidic consumable fabricated from cyclic olefin copolymer
• Honeybun viscometer for viscosity measurement and self-loading assessment

Main Results and Discussion

Solvent and surfactant limits for self-loading in the Bun channel include:

• DMSO: up to 25 percent (v/v)
• Methanol: 12.5 percent (v/v); Ethanol and Acetonitrile: 6.3 percent (v/v)
• Acetone: 5 percent (v/v); Acetic acid: 3.1 percent (v/v)
• Surfactants (Polysorbate 20, Polysorbate 80, Poloxamer 188): below 0.05 percent (v/v)
• Non-ionic and non-polar oils (1-Octanol, 1-Decanol, Silicone oil, Mineral oil): not compatible

Material compatibility of COC indicates high resistance to acids (hydrochloric, sulfuric, nitric), bases (sodium hydroxide, ammonia), water, alcohols and ketones, but rapid degradation with non-polar organic solvents such as toluene, benzene, alkanes and petroleum ethers.

Benefits and Practical Applications of the Method

• Enables low-volume, high-precision viscosity screening for biologics and injectables
• Supports formulation optimization by identifying solvent and surfactant concentration limits
• Reduces sample consumption and accelerates throughput in QA/QC laboratories

Future Trends and Potential Applications

Expansion of solvent and additive libraries, extension to non-aqueous and complex formulations, integration with automated high-throughput platforms and incorporation into regulatory-compliant workflows will enhance the impact of microfluidic viscosity analysis in biopharmaceutical research and quality control.

Conclusion

This study establishes clear compatibility boundaries for solvents and surfactants in the Bun microfluidic device and confirms the chemical resilience of COC. These insights provide practical guidance for selecting suitable formulation conditions and ensuring accurate viscosity measurements in biopharmaceutical applications.