BP Publishes Key Insights on Limits in Chromatographic Tests

In August 2026, the British Pharmacopoeia (BP) published a "Key Insights" article exploring the role and design of limits in BP monographs, with a focus on three related topics.

The article covers:

• The role of the BP Commission's Expert Advisory Groups (EAG) in setting limits
• The approach taken when defining content/assay limits
• Why related substances tests may use either numerical or non-numerical (comparison-based) limits

In particular, the current article highlights that limits in the BP are not merely numbers in a specification, but represent scientific and regulatory judgements about critical quality attributes. The article also clarifies the distinction between the two approaches: non-numerical limits demonstrate compliance by comparison, while numerical limits demonstrate compliance by measurement and calculation.

This latest article builds on the BP's previous Key Insights publication from April 2026, which focused on chromatography in the BP and selected system suitability test (SST) requirements described in the chapter "Chromatographic Separation Techniques".

For more information please see the British Pharmacopoeia Key Insights.