7.3

ANALYTICS TOOLS ON PROCESS UNDERSTANDING AND

HIGH THROUGHPUT PROCESS-DEVELOPMENT

Biotechnology and pharmaceutical companies are increasingly facing external

pressure to develop vaccines not only in shorter process development timelines but

also for them to be more affordable and accessible worldwide. Thus, it is funda-

mental to give solid steps in process development from the early beginning, which

can be potentiated through in-parallel tools and strategies contributing to process

understanding and characterization. The process understanding can be enhanced

through novel strategies such as process analytical technology (PAT), which con-

sists of designing, analyzing, and controlling manufacturing through timely mea-

surements of critical quality and performance attributes. The goal is to achieve a

better control strategy of the process and the effect of scale-up. (This subject is

extensively described in Chapter 8).

Nowadays in the pharmaceutical industry, the development is performed by the

concept of quality by design (QbD), where it begins with predefined objectives,

emphasizes product and process understanding and control based on risk man-

agement [2,68]. Even for downstream processing optimization, which essentially

relies on physicochemical properties not entirely known, are strategies such as

design of experiments (DoE) that contribute to the increase of knowledge. For

experimental evaluation, high throughput screening (HTS) and high throughput

experimentation (HTE) are promising tools for process development [69].

The use of HTS and HTE for process development (PD) is the strategy currently

being applied in big biopharma companies. This strategy is a much smarter way to

generate process knowledge, settle in mechanistic modeling-based approaches that

will allow a safer tech transfer due to process automation, reduction of human

intervention, and consequently minimize the risk of process failure. For this me-

chanistic and predictable view of process design, it is important to have good

analytical tools that enable process automation and optimization.

Analytical tools are fundamental for both process development and process under-

standing, being also essential to reach a characterized final product regarding its quality

and safety (Figure 7.6). Besides the traditional quantification methods, size exclusion

HPLC, capillary zone electrophoresis, dynamic light scattering (DLS), surface plasmon

resonance (SPR), asymmetry flow fractionation, and electron microscopy are methods

used to complement the full characterization of the viral particles. These assays allow to

evaluate product fragmentation, aggregation, and variants that contribute to micro-

heterogeneity [70]. Mass spectrometry-based methods are one of the powerful methods

that can provide valuable insights about virus particle composition, structure, con-

formational stability, assembly, maturation, interactions with other viral and cellular

biomolecules, and changes induced in viruses by external factors as bioprocess op-

eration conditions [71,72]. Analytical ultracentrifugation (AUC) is a highly accurate

technique to quantify empty and genome-containing capsids, as this method has been

the method of choice for adenovirus and adeno-associated virus [73,74].

The tendency in analytical tools is improving the PAT tools for monitoring and

process developing (up- and downstream) in a faster manner, and also the translation

of tools currently used in the analytical setting, towards process monitoring and PAT.

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