Evaluating the impacts of pumping stress on aggregate formation during Tangential Flow Filtration

Biologics i.e. proteins, are complex macromolecules which can undergo physical and chemical degradation during the manufacturing process which can result in product losses or loss of activity. Botulinum toxins (BoNTs) are a class of biologic which are used in therapeutic and cosmetic applications. The botulinum toxin is a 150 kDa metalloprotease protein produced by Clostridium botulinum and is extremely specific in its mechanism of action.
Due to the high potency of BoNTs, the Drug Substance is manufactured at small scale; production scale <5L utilising lab scale equipment. Consequently, Tangential Flow Filtration (TFF) is performed using peristaltic pumps as there are no low shear alternatives e.g. rotary lobe pumps.
During the manufacturing process multiple TFF steps are required to concentrate and buffer exchange the product into the required concentration/formulation for forward processing and during these steps significant losses have been observed due to aggregation of the product.
The exact cause of this product loss is unknown, it has been hypothesised that aggregation is driven by the act of pumping the product within the TFF system, not due to shear stresses caused by the filter its self. These stresses can be caused by a number of mechanisms, shear stress in the pump, cavitation and bubble popping within the pump head resulting in air/liquid interfaces as well as solid/liquid interfaces etc. and can also be influenced by the buffer formulations in which the TFF is performed. Control of stress related aggregation during the manufacturing process is key to development of efficient/robust manufacturing processes.

The CDT has a proven track record of delivering impact from its research and training activities and this will continue in the new Centre. The main types of impact relate to: (i) provision of highly skilled EngD and sPhD graduates; (ii) generation of intellectual property (IP) in support of collaborating companies or for spin-out company creation; (iii) knowledge exchange to the wider bioprocess-using industries; (iv) benefits to patients in terms of new and more cost effective medicines, and (v) benefits to the wider society via involvement in public engagement activities and impacts on policy.

With regard to training, provision of future bioindustry leaders is the primary output of the CDT and some 96% of previous EngD graduates have progressed to relevant bioindustry careers. These highly skilled individuals help catalyse private sector innovation and biomanufacturing activity. This is of enormous importance to capitalise on emerging markets, such as Advanced Therapy Medicinal Products (ATMPs), and to create new jobs and a skilled labour force to underpin economic growth. The CDT will deliver new, flexible on-line training modules on complex biological products manufacture that will be made available to the wider bioprocessing community. It will also provide researchers with opportunities for international company placements and cross-cohort training between UCL and SSPC via a new annual Summer School and Conference.

In terms of IP generation, each industry-collaborative EngD project will have direct impact on the industry sponsor in terms of new technology generation and improvements to existing processes or procedures. Where substantial IP is generated in EngD or sPhD programmes, this has the potential to lead to spin-out company creation and job creation with wider economic benefit. CDT research has already led to creation of a number of successful spin-out companies and licensing agreements. Once arising IP is protected the existing UCL and NIBRT post-experience training programmes provide opportunities for wider industrial dissemination and impact of CDT research and training materials.

CDT projects will address production of new ATMPs or improvements to the manufacture of the next generation of complex biological products that will directly benefit healthcare providers and patients. Examples arising from previous EngD projects have included engineered enzymes for greener pharmaceutical synthesis, novel bioprocess operations to reduce biopharmaceutical manufacturing costs and the translation of early stem cell therapies into clinical trials. In each case the individual researchers have been important champions of knowledge exchange to their collaborating companies.

Finally, in terms of wider public engagement and society, the CDT has achieved substantial impact via involvement of staff and researchers in activities with schools (e.g. STEMnet), presentations at science fairs (Big Bang, Cheltenham), delivery of high profile public lectures (Wellcome Trust, Royal Institution) as well as TV and radio presentations. The next generation of CDT researchers will receive new training on the principles of Responsible Innovation (RI) that will be embedded in their research and help inform their public engagement activities and impact on policy.