Analytical

Evaluation of a Variable-Pathlength Spectrophotometer: A Comparable Instrument for Determining Protein Concentration

Protein concentrations in bioprocessing are determined by multiplying the measured absorbance of UV light as it passes through a sample by the protein extinction coefficient. Conventional spectrophotometer measurements are based on a fixed pathlength depending on the cuvette used to hold the sample (typically 10 mm). Only a small portion of the UV curve is linear at that pathlength. As a result, conventional spectrophotometers have a limited linear range and are unable to measure a large range of protein concentrations…

Special Report on Product Stability Testing: Developing Methods for New Biologics and Emerging Markets

Stability testing is a vital part of product development and is conducted throughout a product’s life cycle (Figure 1). Stability is part of a biotherapeutic’s quality target product profile, and results help analysts understand how critical quality attributes (CQAs) of both drug substances and products are influenced under specific conditions of temperature, relative humidity (RH), light, storage, pH, and other factors. Manufacturers conduct stability tests to determine degradation pathways and establish shelf lives and storage conditions of their products, for…

BioProcess Theater: Analytical Services

BioProcess International launched about the same time as a major FDA regulatory announcement that has radically altered biopharmaceutical development: The quality by design (QbD) initiative is an important part of the agency’s 21st-century good manufacturing practice (GMP) approach, which is changing how regulators review product applications and thus how companies must approach them (1). It has placed increasing pressure on analytical laboratories, whose work is more important to the success of biotherapeutic products than ever before. Backed by harmonized tripartate…

Hamster Phospholipase B-Like 2 (PLBL2): A Host-Cell Protein Impurity in Therapeutic Monoclonal Antibodies Derived from Chinese Hamster Ovary Cells

All recombinant protein biotherapeutics must be tested for the presence of residual host-cell protein (HCP) impurities (1–3). The most common analytical method for doing so is a polyclonal sandwich immunoassay. Polyclonal anti-HCP antibodies are selected to recognize the broadest population of HCPs possible. The immunogen and analytical standard are produced from a blank-run fermentation that mimics the production run but lacks the specific biotherapeutic protein. Because of the large number of impurities present in harvested cell-culture fluid (HCCF) that might…

Building a Robust Biological Assay for Potency Measurement

Potency is a critical quality attribute of a biological product and is often determined by a biological assay (also called bioassay or biopotency assay). Specifically, potency is the biological activity or capacity of a product directly linked to its clinical efficacy. Potency tests are performed as part of product release, comparability studies, and stability testing. Nonbiological methods — which measure a product’s molecular or biochemical characteristics (e.g., ligand-binding assay) — have gained interest as replacements for often troublesome bioassays. Even…

Improved Fluorescent Labeling Efficiency of N-Linked, High-Mannose Oligosaccharides: Using 8-Aminopyrene-1,3,6-Trisulfonic Acid (APTS) for Analysis of Glycoproteins

Glycosylation of proteins, including monoclonal antibodies (MAbs), is recognized as important for the efficacy, immunogenicity, antibody-dependent cell-mediated cytotoxicity (ADCC), and complement-dependent cytotoxicity (CDC) of biotherapeutics (1–6). So research and development of protein candidates is increasingly focused on the effects of glycosylation and how its pathway is affected in the Golgi system of cells involved in biosynthetic processes (7). Such attention on glycosylation has helped advance analytical technologies such as high-pH anion-exchange chromatography (HPAEC) (8); normal-phase chromatography (NP- HPLC), hydrophilic-interaction chromatography…

Modern Laboratory Design: Creating a Space for Effective Collaboration

When asked to envision a modern biotechnology laboratory, lay persons might describe what they’ve seen on an episode of CSI: Miami. Gleaming glass and striking colored lights might look good on television, but they are not what biological researchers need to do their work most effectively. Most of the real biological laboratories I’ve visited, in fact, have been stark, white, fluorescent-lit environments that more resemble something out of 2001: A Space Odyssey. But those are becoming passé. The newest concepts…

Ask the Expert: Accelerating Bioprocess Development Using Shake-Flask Metabolic Activity Data

with Dr. Gernot John of PreSens Precision Sensing GmbH Shake flasks are simple, low-cost devices widely used in screening and media optimization. The most widely measured parameter to determine biomass is optical density (OD). It is typically measured offline because no suitable equipment for broad range biomass measurements in shake flasks has been available. But a new, compact, SFR vario device from PreSens Precision Sensing can be placed under shake flasks to measure four parameters online: pH, O2 saturation, oxygen…

Unwanted Immunogenicity: From Risk Assessment to Risk Management

Although vaccines and immunotherapies are designed to engage the human immune system in fighting disease, unwanted immunogenicity can be a major problem for protein-based therapeutics. Some patients produce antidrug antibodies (ADAs), which might lead to drug inactivation or adverse effects. Even human and humanized proteins have proven to be surprisingly immunogenic in some cases, suggesting that immune tolerance requires careful consideration in biologic product design. In rushing to deliver new drugs to market, some biotherapeutics developers have overlooked factors that…

Understanding and Controlling Sources of Process Variation: Risks to Achieving Product Critical Quality Attributes

Biopharmaceuticals include recombinant proteins, vaccines, gene therapies, and drug products derived from stem cell technology. One key characteristic of shared by all biologics is that they tend to be extremely large molecules with complex three-dimensional structures, critical to their functionality. For example, monoclonal antibodies (MAbs) are composed of more than one thousand times larger than a molecule of aspirin (one analogy compares the complexity of a MAb to that of an F16 jet, and the complexity of aspirin to that…