Since nearly all biopharmaceuticals are administered by injection or infusion a platform approach to formulation might seem attractive as a way to streamline biopharmaceutical development. The diversity of biopharmaceuticals, however, even within certain molecular classes, unfortunately precludes a one-size-fits-all approach to formulation and formulation analysis. Platform formulations often fail to provide stability, deliverability, potency, and amenability to analytics.
Most biotherapeutics are prepared and stored in buffers, but formulations differ significantly from basic compositions of protein, salt, and water. Even within specific molecular classes, balancing effectiveness, safety, and ease of analysis often requires the addition of excipients, modifiers, detergents, adjuvants, and/or stabilizers. Each additive introduces a new set of issues for the subsequent analysis of the drug product.
For example, the common stabilizer human serum albumin, significantly increases ultraviolet absorption at 280 nm, a standard concentration measure used in HPLC analysis. Other formulation components may interfere with analysis by electrophoresis or HPLC. Introducing excipients or changing the buffer to improve stability, while scientifically justified, will cause at the very least a reassessment, if not an overhaul, of associated analytics.