The fundamental assumption of in-silico scale-up and scale-down of chromatography is that only the fluid dynamics outside the pore system change. Once a molecule enters the pore system, diffusion, adsorption, and desorption are following the same mechanism from a 96-well filter plate up to a production scale column.<br/>To obtain adsorption isotherm parameters for column modeling, batch measurements are typically corrected using an “equivalent column volume” factor. In a per-well capacity study of filter plates prepared with a ResiQuot device, considerable well-to-well differences could be found and, most importantly, deviations from the expected equivalent column volume result in wrong predictions of column experiments.<br/>To solve this, we present a modified computational method for fitting batch isotherms to mechanistic model equations that relies only on the applied and measured supernatant concentrations. An assumption on the resin amount in the well is not needed anymore. To this, the isotherm equation is reformulated to include the liquid-to-solid ratio (L/S) as model parameter. Using this method, the average L/S in a 96-well plate filled with SP Sepharose FF could be determined from a single isotherm at constant ionic strength. The resulting binding capacity coincides with the average per well measurements, and the isotherm parameters could be used to predict a break-through curve on a 16ml lab-scale column.

Modified batch isotherm determination method for mechanistic model calibration

255th National Meeting (2018)

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