Author Archives: Venkatesh Srinivasan

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

Developing an End-to-End Scale-Down Model for a Commercial-Scale Downstream Process: Enhancing Technology Transfer Efficiency

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Large and complex protein molecules used as therapeutic agents are manufactured in a series of process steps that start with thawing of cell-bank vials and finish with filling and packaging (Figure 1). The cost and complexity of commercial-scale biomanufacturing processes make them prohibitive to troubleshoot or experiment at full commercial scale. Biopharmaceutical companies routinely use scale-down models (SDMs) of licensed commercial-scale processes to evaluate raw material changes, process improvements, and deviations (1) (Figure 2). Here, we outline some considerations in…

March 14, 2019

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

Qualification of Scale-Down Bioreactors: Validation of Process Changes in Commercial Production of Animal-Cell-Derived Products, Part 1 — Concept

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Implementing continuous process improvements is increasing in priority for the biopharmaceutical industry. Such implementation can be driven by product safety, purity, and stability enhancement opportunities as well as by cost-reduction pressures. Companies invest in projects to improve product quality assurance, safety, and yield as well as production efficiency (1). Such changes may come at any process stage, from early cell-growth methods through final-product packaging improvements. Examples include growth medium optimization, purification column operation optimization, and enhanced recovery during final filling…

May 1, 2014

Process Improvements Increase Production Capacity of a Legacy Product

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Implementation of postlicensure process improvements in the biopharmaceutical industry can benefit patients and drug manufacturers alike. Here we demonstrate through a case study how a change to the cell culture medium and process can be taken from proof of concept through scale-up to demonstration of feasibility. We further illustrate the scope and complexity of implementing a change in commercial manufacturing to realize significant benefits such as increased production capacity over an existing legacy process. The Importance of Postapproval Improvements Drug…

November 1, 2013