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

Importance of Topic

The accurate and efficient measurement of pH is critical throughout biologic drug development, affecting buffer preparation, formulation stability monitoring, and quality control. Traditional manual pH measurements are time-intensive, prone to error, and require frequent probe calibration and cleaning between samples. An automated high-throughput solution addresses these limitations and accelerates formulation screening.

Objectives and Study Overview

This study evaluated the performance of an automated pH measurement arm integrated into the Big Kahuna and Junior liquid-handling platforms. The goals were to compare throughput, precision, and accuracy against manual benchtop pH meters across a diverse set of buffer conditions, with and without added protein (human IgG).

Methodology and Instrumentation

An automated pH arm featuring four Orion ROSS Micro glass pH electrodes spaced at 27 mm pitch was used to measure 16 buffer formulations spanning pH 4.5–8.0, at 20 or 100 mM buffering capacity, and with or without 300 mM NaCl. Each condition was tested in triplicate wells of 96-well plates. For protein studies, buffers were supplemented with 10 mg/mL human IgG. Daily automated calibrations employed pH 4.00, 7.00, and 10.00 Ricca standards. Probes were rinsed in deionized water and dried with an on-deck air knife between measurements.

Main Results and Discussion

Automated measurements of buffer pH were within ± 0.05 pH units of manual readings for all 16 conditions, with standard deviations typically under 0.02. Similar precision and accuracy were maintained when protein was present. Across five replicates of each 96-well plate (480 total readings), no drift or sample carryover effects were observed despite rapid sequential measurements of varying buffer compositions and ionic strengths.

Benefits and Practical Applications

• High throughput: 96-well plate read in approximately 45 minutes versus hours manually.
• Reproducibility: Consistent performance across multiple probes and runs.
• Flexibility: Compatible with diverse buffer types, ionic strengths, and protein-containing samples.
• Reduced hands-on time: Automated calibration, washing, and drying streamline workflow.

Future Trends and Opportunities

Further integration with advanced liquid-handling and data analytics could enable real-time formulation optimization. Expansion of the system to handle alternative electrode types or online buffer preparation may broaden applicability. Incorporating feedback loops for automated buffer adjustment could realize end-to-end pH control in biologic formulation pipelines.

Conclusion

The automated pH arm on Big Kahuna and Junior delivers precise, accurate, and high-throughput pH measurements across biologic formulation conditions, matching manual benchtop performance while reducing hands-on effort.

Reference

Unchained Labs. High-throughput automated pH measurements for biologics formulations on Big Kahuna and Junior. Application Note. 2018.