Author Archives: Yuval Shimoni

eBook: Product Variants in Bioprocesses

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Product variants are contaminants because they bear properties that are different from those of desired biological products with respect to activity, efficacy, and safety. Thus, such variants can compromise product quality and consistency. In this eBook, Yuval Shimoni explores different types of variants — including primary-sequence variants, undesirable posttranslational modifications, aggregates, and degraded proteins — and explains how their presence can diminish the performance and quality of drug substances and products. He also discusses how product variants form at different…

August 30, 2021

Compounded Media Powder Streamlines Cell Culture Media Preparation Operations

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Cell culture medium is critical to cell growth, metabolism, and protein expression. It provides for optimum pH, osmolality, and nutrients in an environment that is essential for cell survival, growth, and expression of proteins and/or metabolites and drug-substance modalities of interest (1). A complete medium typically contains basic nutrients such as carbohydrates, amino acids, lipids, salts, vitamins, trace metals, growth factors/hormones (e.g., insulin), antishear factors, and other chemicals that facilitate cell growth and protein expression and may stabilize recombinant protein…

March 9, 2021

Product Quality Attribute Shifts in Perfusion Systems, Part 2: Elucidating Cellular Mechanisms

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Part 1 of this two-part report describes an investigation into the potential cause(s) and ways to control a product quality attribute (PQA) of a protein expressed in perfusion cell culture (1). The presence of low–molecular-weight (LMW) species following size-exclusion high-performance liquid chromatography (SEC-HPLC) is a protein quality attribute that can indicate an increase in truncated forms of the expressed protein and/or other LMW moieties. The expressed protein in this study is a heavily glycosylated recombinant glycoprotein (rGP) comprising two subunits:…

December 17, 2020

Product Quality Attribute Shifts in Perfusion Systems, Part 1: Identifying Shifts When They Occur

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Perfusion cell culture processes are continuous, with fresh media continuously added and spent media (harvest) removed simultaneously through a cell-retention device (Figure 1). To maintain specific bioreactor cell density, cells are removed periodically as cell bleed or discard. Perfusion systems offer a number of advantages over batch and fed-batch culture modes such as lower capital costs and an ability to support higher cell densities with better viability over longer manufacturing campaigns requiring shorter turn-around times. However, perfusion systems require complex…

September 22, 2020

The Upstream Perspective: Taking Efficiency Beyond Cell-Line Development

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With 20 years of experience in the biopharmaceutical industry — at Genentech, Applied Biosystems, Cell Genesys, Cellerant Therapeutics, and Bayer — Yuval Shimoni has written frequently for BioProcess International on a number of production topics. Those have ranged from process improvements and bioreactor scale-down validation, to raw materials management, to addressing variability and virus contamination events. For this featured report, we discussed hardware and instrumentation, quality by design (QbD) and related approaches, and other strategies that can take expediting upstream…

June 16, 2020

A Response Plan for Viral Contamination in Bioproduction Facilities

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The biopharmaceutical industry uses living biological systems as a platform for manufacturing of protein-based drugs, vaccines, and other therapies derived from or consisting of different cell types. On one hand, living systems are inherently susceptible to viral infection and may harbor endogenous viruses, so the potential for such contamination cannot be eliminated. On the other hand, the industry has an excellent patient-safety record. Viral safety is achieved through three fundamental measures: prevention (e.g., by selection), removal (by clearance and/or reduction),…

March 3, 2020

Reducing Variability in Cell-Specific Productivity in Perfusion Culture: A Case Study

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Variation in bioproduction is recognized in the industry and often attributed to one or more of four sources: raw materials (including consumables), operational inputs (measurements, methods, personnel, equipment), environmental factors, and biological variation inherent to living cells (1). Variability can occur even among replicate units regardless of production mode (e.g., fed-batch or perfusion), and it can manifest as variability in productivity, cell metabolism, and/or product quality (2–4). In commercial biomanufacturing, meeting all product quality attributes is a requirement for regulatory…

February 16, 2018

Viral Risk Evaluation of Raw Materials Used in Biopharmaceutical Production

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Ensuring a continuous supply of safe medicines to patients is a key objective for both health authorities and the pharmaceutical industry. A critical component to that end is maintaining a reliable supply of qualified raw materials (RMs). Manufacturers must ensure not only the suitability of RMs for their intended use in a manufacturing process, but also their highest attainable safety with regards to viruses and other adventitious agents. The need to apply a risk-based RM control strategy is in line…

October 14, 2016

A Risk-Based Approach to Supplier and Raw Materials Management

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Ensuring a continuous supply of safe medicines is a key objective for the pharmaceutical industry and health authorities alike. A critical component to that end is maintaining a reliable supply of qualified raw materials (RMs) used in drug production. However, changes in suppliers, their processes, their providers, and consequently the materials they supply can occur (for a number of reasons) at any time during the life cycle of drug production. A product-supply organization therefore must be prepared to address such…

November 17, 2015

Qualification of Scale-Down Bioreactors: Validation of Process Changes in Commercial Production of Animal-Cell-Derived Products, Part 2 — Application

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Here we apply our approach to validation of animal cell culture process changes using qualified, scale-down bioreactors. As described in Part 1 (including Table 1, Figures 1 and 2, and References 1–23), the goal is to facilitate implementation for the benefit of both the patients and industry. “Qualification of Scale-Down Bioreactors: Validation of Process Changes in Commercial Production of Animal-Cell–Derived Products, Part 1 — Concept†appears on pages 38–45 of BioProcess International’s May 2014 issue. Process changes often entail validation,…

June 1, 2014