New ultra scale-down principles for monoclonal antibody recovery and purifications

The development of manufacturing processes for biopharmaceuticals is carried out by performing experiments in the laboratory and then the pilot plant. These laboratory - scale experiments are often misleading as they do not allow for the effect of the large-scale processing environment on the properties of biological process material. The research contained within this thesis seeks to develop laboratory techniques capable of eliciting the effects of the processing environment on the material and of predicting the performance of large-scale unit operations used in the purification of monoclonal antibody (MAb) biopharmaceuticals using milliliter volumes of process material. Two key interactive stages were examined firstly, an early centrifugation clarification stage designed to prepare material for subsequent filtration which precedes the second stage studied, a high affinity antibody capture step. The first focuses on the whole cell broth, containing the contaminants and the antibody product, the latter on the antibody product itself. A scale-down centrifuge technique which employed a rotating-disc, centrifuge feed zone mimic along with a laboratory-scale centrifugation method were developed to predict the clarification performance of two pilot, disc stack centrifuges with differing feed zone configurations and a manufacturing-scale disc stack centrifuge. The material obtained from the scale-down centrifuge protocol was shown to be equivalent to that from one of the pilot centrifuges to which it had been compared and, hence, could be used for the development of subsequent unit operations, such as chromatography processes. A method was developed to predict the elution profile of an 18 L pilot affinity chromatography column using a scale-down column with a column volume of one milliliter. A regime analysis of the laboratory-scale chromatography system was performed using conductivity transitions to determine the extent of additional zone broadening occurring at the small scale so that the prediction of the large-scale elution volume and eluting product concentration could be significantly improved.