The number of biotherapeutics on the market has rapidly increased during the past several years. Such proteins commonly exhibit a concentration-dependent propensity for self-association, which often leads to the formation of aggregates that range in size from nanometers (oligomers) to microns (subvisible and visible particles). Publications two years ago focused attention on the potential immunogenicity of active-ingredient aggregates ((1,2,3,4). The authors discussed lack of specificity of compendial measurements and inability of other current methods to address potential effects…
QA/QC
Imaged Capillary Isoelectric Focusing for Charge-Variant Analysis of Biopharmaceuticals
Analyzing charge variants of therapeutic proteins is critical for characterizing and monitoring quality attributes of antibodies. Charge variants include deamidation, formation of N-terminal pyroglutamate, aggregation, isomerization, sialylated glycans, antibody fragmentation, and glycation at the lysine residues. In some cases, such changes affect binding, biological activity, patient safety, and shelf life. The biopharmaceutical industry relies on tools such as ion-exchange chromatography (IEC), isoelectric-focusing gel electrophoresis (IEF), and capillary equivalents such as capillary isoelectric focusing (CIEF) and imaged CIEF (iCIEF)…
Limited Analytical Technologies Are Inhibiting Industry Growth
Progress in the development of bioprocessing-related assays and analytical instrumentation has not kept up with industry demands. The industry wants analytical technologies (especially for single use) to help improve productivity, optimize and monitor processes, provide real-time product quality control, and characterize biosimilars. These trends are reflected in our recent survey data. Over 30% of biopharmaceutical manufacturers and contract manufacturing organizations (CMOs) have expressed demands for improved assays and analytical equipment (1). BioPlan Associates’ eighth annual survey of biopharmaceutical…
Implementation of the ASTM Standard for Manufacturing Systems Verification
In 2007, ASTM International (ASTM), formerly known as the American Society for Testing and Materials, published its “E2500-07” international industry consensus standard for conducting a risk-based design and qualification of good manufacturing practice (GMP) manufacturing systems (1). This guide incorporates risk- and science-based practices to focus on critical aspects affecting equipment systems throughout their design–qualification–operation lifecycle. Presentations at recent PDA and ISPE annual meetings indicate that the bioprocess industry is embracing E2500 to improve system designs and reduce costly validations.…
Comparing H1N1 Virus Quantification with a Unique Flow Cytometer and Quantitative PCR
A novel influenza A (H1N1) virus was discovered in Mexico in early 2009 (1). Infections from this strain led to declaration of a pandemic midyear, with about 61 million patients and 13,000 deaths reported by the US Centers for Disease Control (2). Although the pandemic officially ended in August 2010 (3), vaccines are still in demand to protect people against the H1N1 strain that is now expected to circulate seasonally for years to come. To best respond to…
Distinctions Between Analytical and Bioanalytical Test Methods
Analytical methods used for characterization, release, and stability testing of biotechnological/biological products are often automatically referred to as “bioanalytical” methods by some in the field. Many times the term is used to distinguish between test methods applied to small-molecule chemical products and those for macromolecular, biologically based products. It seems sensible enough: We use analytical methods to test chemical pharmaceutical products, so aren’t test methods used for biopharmaceutical products therefore bioanalytical methods? Any way, who cares whether the term is…
Protein Conjugates
Methods and Materials Thanks to vendors large and small — such as Invitrogen (www.invitrogen.com), ProteoChem (www.proteochem.com), Sigma Aldrich (www.sigmaaldrich.com), Soltec Ventures (www.soltecventures.com), and Thermo Scientific Pierce (www.piercenet.com) — bioconjugation chemistry is a field of many options. For example, amine coupling of lysine amino-acid residues typically involves amine-reactive succinimidyl esters. Sulfhydryl coupling of cysteine residues uses a sulfhydryl-reactive maleimide. Photochemically initiated free-radical reactions offer broader reactivity. Most processes couple small molecules to proteins or proteins to one another (e.g., antibodies…
Protein Therapeutics and Aggregates Characterized By Photon Correlation Spectroscopy
New biological entities (NBEs, therapeutic proteins such as interferons or antibodies) are much more complex than new chemical entities (NCEs), the classic “chemical†active ingredients. First, they are much larger. The average molecular weight of antibodies is ~150,000 g/mol. Second, most NBEs contain three-dimensional structural elements — with the protein secondary and tertiary structure being the most prominent, but quaternary structures are also known for some. The 3D structures are essential for correct bioactivity (1), but they are…