High-throughput automated pH measurements for biologics formulations on Big Kahuna and Junior

Importance of the Topic

Accurate and efficient pH measurement is critical in biologic drug formulation, impacting buffer preparation, stability monitoring, and overall product quality. Traditional manual pH determinations are labor-intensive, error-prone, and limited to one sample at a time, creating bottlenecks in high-throughput formulation screening.

Objectives and Overview

This study evaluates an automated pH arm integrated into the Big Kahuna and Junior liquid-handling platforms for high-throughput pH measurement of biologics formulations. Sixteen buffer compositions, with and without human IgG, spanning pH 4.5 to 8.0 and varying buffer types, concentrations, and salt content, were tested in a 96-well format. The goal was to compare automated measurements against manual benchtop results to assess precision, accuracy, and workflow efficiency.

Methods

Buffers (acetate, citrate, phosphate, tris at 20 or 100 mM, ±300 mM NaCl) were prepared manually and supplemented with 10 mg/mL hIgG where indicated. Samples were aliquoted into 96-well plates (300 µL/well for buffer only, 80 µL/well for protein samples). Each plate was measured five times for a total of 30 replicates per condition. Automated measurements employed a wash-and-dry protocol between readings to minimize cross-contamination.

Used Instrumentation

• Big Kahuna and Junior automated liquid-handling systems (Unchained Labs)
• Four-probe pH arm with Orion ROSS Micro glass pH electrodes (Thermo Scientific)
• Consort C3011 multiparameter benchtop pH meter for manual comparison
• Ricca calibration solutions at pH 4.00, 7.00, and 10.00
• On-deck deionized water wash station and air knife drying station

Main Results and Discussion

Automated pH readings for all buffer conditions, with and without protein, were within ±0.05 pH units of manual measurements. Precision across 30 replicates showed standard deviations below 0.02 pH units. No systematic bias was observed due to buffer composition, salt concentration, or protein presence. Consistency was maintained across all four probes and across five sequential plate runs. A full 96-well plate was processed in approximately 45 minutes, representing a significant throughput improvement over manual methods.

Benefits and Practical Applications

• Substantial reduction in hands-on time and manual pipetting steps
• Parallel, high-throughput measurement suitable for formulation screening
• Robust performance across diverse buffer types, concentrations, and protein content
• Minimized risk of cross-contamination via automated wash and dry steps
• Enhanced reproducibility and data quality compared to single-probe manual workflows

Future Trends and Opportunities

Advances may include integration with laboratory information management systems (LIMS) for automated data capture, expansion to multi-parameter measurements (e.g., conductivity, osmolality), development of probe technologies for extreme pH or low-volume samples, and application of machine-learning algorithms to optimize formulation screening based on rapid pH data.

Conclusion

The Big Kahuna and Junior automated pH arm delivers fast, accurate, and reproducible pH measurements for high-throughput biologics formulation development. By enabling parallel analysis of 96-well plates with minimal user intervention, this solution addresses key challenges in formulation screening and quality control, accelerating the development timeline while maintaining data integrity.