Let it flow: automated low volume viscosity measurements with Junior

Importance of the Topic

High concentration monoclonal antibody formulations are essential in biologic drug development but often exhibit elevated viscosity that complicates manufacturing and administration. Accurate viscosity assessment at final formulation concentrations informs developability and formulation strategies.

Objectives and Study Overview

This study compares automated low volume viscosity measurements using the Junior or Big Kahuna system equipped with a micro capillary viscosity station against a manual microVISC benchtop viscometer. Key aims include validating accuracy, precision, throughput, and sample consumption for glycerol standards and a monoclonal antibody concentration series.

Instrumentation Used

• Junior or Big Kahuna micro capillary viscometer with viscosity station
• Rheosense microVISC viscometer
• LEA software suite including Library Studio Design Creator, Automation Studio, and Analysis Add-in

Methodology and Instrumentation

The micro capillary system measures pressure changes when injecting 100 microliters of sample at user defined flow rates and temperature. Calibration employs glycerol standards across 0 to 70 percent weight per weight concentrations to determine the capillary inner radius using known viscosities. Measurements run at 20 degrees Celsius and 15 microliters per second injection rate. The microVISC system analyzes samples at ambient temperature requiring larger sample volumes per measurement. Both platforms tested triplicate measurements of glycerol standards and mAb samples.

Results and Discussion

Automated measurements on the micro capillary viscometer matched published glycerol viscosities with a slope of 0.9971 and R2 of 0.9999 demonstrating high accuracy and reproducibility. The microVISC exhibited lower slope due to lack of temperature control. Monoclonal antibody viscosity increased exponentially with concentration reaching 9.49 centipoise at 150 milligrams per milliliter. The automated system delivered low standard deviations and consistent results with minimal hands on intervention and high throughput.

Benefits and Practical Applications

The automated low volume approach reduces sample consumption to 100 microliters per test, conserving valuable biologic material. User defined temperature and flow control extend analytical flexibility across Newtonian and non Newtonian fluids. High throughput enables screening of formulation variants during early stage development and supports quality control in biopharmaceutical manufacturing.

Future Trends and Opportunities

Integration of viscosity analysis into automated workflows will accelerate formulation optimization. Combining real time viscosity monitoring with process analytical technology and predictive modeling may enable adaptive process control. Advances in micro fluidic sensors and integration with artificial intelligence can further enhance sensitivity and throughput for complex biologic formulations.

Conclusion

Automated micro capillary viscometry on the Junior or Big Kahuna platform provides accurate, reproducible low volume viscosity measurements suitable for high concentration biologics. Temperature control and automation deliver consistent data aligned with published standards and support efficient formulation development.

References

1. Segur JB and Oberstar HE Viscosity of Glycerol and Its Aqueous Solutions Industrial and Engineering Chemistry September 1951