Protein aggregation underlies many deleterious effects for biotherapeutics. Principal among those are loss of efficacy, induction of unwanted immunogenicity, altered pharmacokinetics, and reduced shelf life. Consequently, aggregation-preventing surfactants are essential components of many protein formulations. They facilitate the development, manufacture, and stability of dosage forms by helping formulators manage protein aggregation and reduce interactions with container and delivery device surfaces. Monoclonal antibodies (MAbs) present difficulties with respect to aggregation because they usually require relatively high doses for therapeutic…
Analytical
Attaining Next-Level Titers in CHO Fed-Batch Cultures
Taking full advantage of high cell-specific productivity of recombinant proteins requires use of robust fed-batch processes involving addition of one or more concentrated nutrient solutions. Proportionately large amounts of concentrated nutrient supplements are often needed to support the stoichiometrically balanced metabolic requirements of high-density cell cultures. Large feed additions ultimately dilute the final product at harvest, but attempts to minimize feed volumes often lead to multiple concentrated acidic and basic subgroups. Those impart additional complexity to manufacturing processes.…
Prior-Knowledge Assessments
Process characterization (PC) studies are experiments performed primarily at laboratory scale to demonstrate process robustness and provide data necessary for planning, risk mitigation, and successful execution of process validation (1, 2). These typically involve extensive, multifactorial testing designed to determine the effects of operational parameter perturbations and raw materials on process performance and product quality (1, 2). Product-specific information from development studies may be used to help guide PC study design; however, such information may be limited or…
A New Kinetic Structured Model for Cell Cultivation in a Chemostat
Mathematically modeling the kinetics of batch and continuous cultivation allows you to not only calculate and evaluate the effects of process parameters, but also to forecast those parameters and duration of cultivation to develop a cost-effective production process. Mathematical modeling microorganism cultivation was intensively developed in the second half of the last century. Equations 1–6: () Monod proposed Equation 1 for batch processes in 1942 (1). In that equation, µ and µmax are the specific and maximum…
A Host Cell Protein Assay for Biologics Expressed in Plants
Host cell proteins (HCPs) can be present in significant amounts in biological products through copurification with a recombinant protein-drug substance. Purified active ingredients developed for human use must be free of all contaminants — including residual HCPs — to minimize the incidence of immunogenicity against a drug product or its trace contaminants (1). HCP assays allow for monitoring host-related impurities during product development and process development. Most are in the enzyme-linked immunosorbent assay (ELISA) format for detecting…
Integrity Testing of Ultrafiltration Systems for Biopharmaceutical Applications
Ultrafiltration (UF) is a membrane-based separation technology commonly used in the biopharmaceutical industry for concentration or diafiltration of protein solutions to remove low–molecular-weight (LMW) impurities or exchange buffers. The nominal MW limit of UF membranes ranges from 1,000 Da (1 kDa) to 1,000,000 Da (1,000 kDa). A target product is retained by the membrane while lower-MW solutes or impurities pass through (1). For a target product with a smaller MW than the impurities, separation is accomplished by allowing…
Enhancing Data Quality with a Partly Controllable System at Shake Flask Scale
In bioprocess development, small-scale systems are used to identify appropriate cell lines, media, and feeds before applying more expensive, controlled cultivation systems at larger scales. Process development relies on data generated in such uncontrolled small-scale cultivation systems, so comparability is an issue. Shake flasks are commonly used for small-scale culture of mammalian suspensions. Incubators provide a suitable environment with carbon dioxide (CO2) supply and humidity control and ensure sufficient oxygen transfer and homogenization of cell suspension by appropriate…
QbD for Biologics: Learning from the Product Development and Realization (A-MAb) Case Study and the FDA OBP Pilot Program
Cosponsored by CASSS (an international separation society) and the FDA, the 23rd CMC Strategy Forum was held in Bethesda, MD, on 19–20 July 2010. For the third time, this forum explored the topic of quality by design (QbD) for biologics. The first such forum was held in July 2007 and focused on establishing a general understanding of QbD terminology and concepts. In July 2008, the second discussed approaches for submission of QbD data and associated regulatory implications. Building…
Legacies in Bioprocessing
Bioprocessing is full of legacies. Our remote ancestors discovered fermentation: microbial magic that transformed fruit to wine and grain to beer. Building on the work of Edward Jenner and others, Edward Ballard systematically reinfected cattle to make vaccines. Louis Pasteur revolutionized both fermentation and vaccination by showing that different microbes caused fermentation and spoilage (saving wine and beer production from disastrous batch contamination), establishing the germ theory of disease, and using that knowledge to develop new vaccines against endemic infections.…
Novel Single-Use Sensors for Online Measurement of Glucose
According to an FDA guidance document, process analytical technology (PAT) tools “are intended to support innovation and efficiency in pharmaceutical development†(1). The agency encourages manufacturers to use a PAT framework for developing and implementing effective innovative approaches in development, manufacturing, and quality assurance. The sensors described here are one possible response to the requirement of systems by analyzing and controlling critical cultivation parameters with real-time process measurements. Working Principle Glucose was measured using a #CITSens…