Use of an alternative scale-down approach to predict and extend hydroxyapatite column lifetimes

Prediction of the performance of pre-packed purification columns through machine learning

Pre-packed columns have been increasingly used in process development and biomanufacturing thanks to their ease of use and consistency. Traditionally, packing quality is predicted through rate models, which require extensive calibration efforts through independent experiments to determine relevant mass transfer and kinetic rate constants. Here we propose machine learning as a complementary predictive tool for column performance. A machine learning algorithm, extreme gradient boosting, was applied to a large data set of packing quality (plate height and asymmetry) for pre-packed columns as a function of quantitative parameters (column length, column diameter, and particle size) and qualitative attributes (backbone and functional mode). The machine learning model offered excellent predictive capabilities for the plate height and the asymmetry (90 and 93%, respectively), with packing quality strongly influenced by backbone (∼70% relative importance) and functional mode (∼15% relative importance), well above all other quantitative column parameters. The results highlight the ability of machine learning to provide reliable predictions of column performance from simple, generic parameters, including strategic qualitative parameters such as backbone and functionality, usually excluded from quantitative considerations. Our results will guide further efforts in column optimization, for example, by focusing on improvements of backbone and functional mode to obtain optimized packings.

Monoclonal antibody purification by ceramic hydroxyapatite chromatography

Hydroxyapatite chromatography is shown to be an excellent method for chromatographically purifying monoclonal antibodies (Mab). Mab contained in eluates from Protein A columns was partially purified on ceramic hydroxyapatite (CHT™) Type I, 40 μm ceramic hydroxyapatite using two scouting methods which provide milligram amounts of Mab typical at laboratory scale. The result from one of the scouting methods was optimized to obtain a high concentration of purified Mab with acceptable clearance of cell culture impurities. Several techniques (linear phosphate screening, linear alkaline salt screening, and two alkaline salt step gradients) are described for obtaining high concentrations of purified Mab in a lab-scale CHT chromatography column.