Developing biopharmaceutical manufacturing unit operations inevitably involves screening chromatographic adsorbents that offer high selectivity and yield highly purified materials. Simultaneously, materials must meet the diverse and rigorous requirements for use in an economically viable cGMP process.
When considering the technical performance of chromatography media, the selection process might involve preparing numerous packed columns, followed by a target protein challenging various candidate adsorbents to allow scrutiny of protein recovery, yield, purity, and activity. Then the capacity, affinity, and selectivity of an adsorbent are considered in the context of process conditions such as binding and elution buffers, or response to repeated clean-in-place (CIP) procedures.
Packed columns have been commonly used in such process development activities. Using packed columns, however, limits the range of media that can be appraised because packing the media in small-scale columns is onerous and may be hindered by the limited availability of (sometimes costly) automated systems that will perform method development or scouting experiments. As a result, optimal adsorbents or even process conditions may not always be realized or implemented.
However, using 96-well microplates containing chromatography media to facilitate high throughput experimentation may rapidly enhance adsorbent selection, thereby allowing a greater opportunity to identify an optimum adsorbent and set of operating conditions. An investigation can facilitate the appraisal of a range of adsorbents in a single plate, or develop the process conditions for a single adsorbent by challenging it with various bind and elute conditions.
Table 1. Summary of dimensions and characteristics of 96-well microplates used for adsorbent selection and process development.
In this article we discuss adapting the high throughput ex-perimental advantage of 96-well microplate technologies for process selection and development. We highlight various aspects that need to be considered in developing a robust and trustworthy system of adsorbent appraisal.
Microtiter plates in a 96-well format have been used for many years in analytical research and clinical diagnostic laboratories because of their high throughput of samples. Examples of their application include the enzyme-linked immunosorbent assay (ELISA) and high-throughput screening of pharmaceutical candidates. The speed, accuracy, and efficiency of these activities is often further enhanced by using robotic systems which can dispense and aspirate relevant fluids into specified areas of the plate, and manage multiple plates simultaneously.
Figure 1. Summary of anticipated and observed effects when ion exchangers are exposed to pH and salinity gradients.