QA/QC

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…