Anion exchange membrane chromatography (AEX) is an attractive alternative to flow-through anion exchange column chromatography.
Replacing AEX column chromatography with AEX membrane chromatography provides similar output but at a much higher load density,
usually greater than 10 kg/L of membrane. The commercially available scale-down model, Sartobind nano, which has a 1 mL membrane
volume, requires a significant amount of material for process development and validation whereas a relatively small amount
of material is typically available during early clinical development. To overcome this limitation, an ultra scale-down device,
Sartobind pico, was developed to reduce material consumption and validation cost. In this article, the development of the
new ultra scale-down device is detailed and scalability to Sartobind nano and to a large-scale capsule are demonstrated. Studies
using model proteins and industrially relevant monoclonal antibody feedstock are described. The new ultra scale-down device,
Sartobind pico, enables process development, characterization, and validation with scalability to large-scale membrane chromatography
devices while reducing sample consumption, time, and cost.
Anion-exchange (AEX) membrane chromatography is an attractive technology for monoclonal antibody (mAb) purification because
of advantages such as elimination of column packing and unpacking, higher throughput, smaller plant footprint, and considerably
less buffer consumption. Compared with AEX resins, which are typically loaded to approximately 100 g/L, AEX membranes can
provide orders of magnitude higher loading capacity in flow-through mode with adequate impurity removal. For example, Zhou
et al. reported greater than 3000 g/m2 or 10.9 kg/L load capacity with > 5 log reduction value (LRV) for four different model viruses (1). In another study, Zhou
et al. showed that a similar LRV for X-MuLV could be obtained at a load capacity of 13 kg/L and at flow rate of 600 cm/hr
(2). Glynn et al. recently described the evolution of Pfizer's antibody purification process from three columns to two by
replacing the resin-based AEX chromatography step with a membrane adsorber and increasing the load capacity of this step by
a factor of 100 (3). The removal of process-related impurities with AEX membrane adsorbers at high load capacity and high
flow rate has also been published by Arunakumari et al. (4). Lately, the authors demonstrated virus removal by membrane adsorbers
with a LRV greater than 4.5 and 4.4 for X-MuLV and MMV, respectively, at 20 kg/L mAb load capacity (5). Mehta et al. showed
that purity and product quality comparable to traditional three-column affinity processes can be achieved with a novel process
using a nonaffinity capture step and membrane-based technologies such as AEX membrane adsorbers and high performance tangential
flow filtration (6).
It is thus well documented in the literature that an AEX membrane adsorber is a powerful alternative to column chromatography
and can facilitate development of new purification strategies for downstream processing in the biopharmaceutical industry
(7). However, the high load capacity achieved with membrane adsorbers in the flow-through mode implies the need for a significant
amount of material for process development with laboratory-scale devices. For example, a load capacity of 10 kg/L means that
10 g of material is required for each experiment with a 1 mL laboratory-scale device. High material consumption can be a limiting
factor, particularly during early stages of drug development where relatively small amount of material is typically available.
Reducing the virus validation cost by minimizing the amount of virus spike required is also of significant interest.
To overcome these limitations, a new ultra scale-down membrane adsorber device, Sartobind pico (Sartorius Stedim Biotech GmbH,
Göttingen, Germany), with a membrane volume of 0.08 mL has been developed. The 12.5-fold lower membrane volume than the current
laboratory-scale device, 1 mL Sartobind Nano, significantly minimizes feedstock and virus spike requirements for development,
characterization, and validation studies. The performance of this device was evaluated using model molecules and industrially
relevant mAb feedstock and was compared with the current scale-down device, Sartobind nano. Data demonstrating the scalability
of the new ultra scale-down device to a manufacturing-scale device are also presented.