USP: Commenting on 'Balances <41>' and 'Weighing on an Analytical Balance <1251>' possible again

The chapters 'Balances <41>' and 'Weighing on an Analytical Balance <1251>' of the USP have been revised again and published on the website of the Pharmacopeial Forum of the USP for comments. The previous drafts have been discarded. Comments and observations on these drafts can be submitted until 30 November 2024.

Balances <41>

In addition to formal changes, adjustments and additions were made in the following areas in particular:

• Introduce the relationship between calibration and performance checks within the life cycle approach to ensure fitness for purpose.
• Include the concept of a risk-based approach with respect to the frequency of calibration and performance checks.
• Add a new section on Calibration, clarifying its purpose and including considerations for uncertainty and frequency.
• Introduce clarifications of compliance with respect to the Repeatability test.
• Align the term minimum weight with that in <1251> and in the European Pharmacopoeia, with regard to standard deviation. Include calculation examples.
• Introduce text that differentiates the minimum weight from the smallest net weight.
• Clarify criteria to ensure compliance with the required accuracy during performance test checks and calibration, including consideration of the uncertainty of the test weights.
• Incorporate additional applicable references into the text.

Weighing on an Analytical Balance <1251>

In addition to formal changes, adjustments and additions were made in the following areas in particular:

• In the Introduction, clarify the group of instruments in which balances are included as per Analytical Instrument Qualification <1058> and its relationship with the analytical target profile described in Analytical Procedure Life Cycle <1220>.
• Add a new section, Principle, defining weight and units.
• In Performance Qualification, the risk of the weighing application is explained with regard to the user’s quality management system in order to define the frequency and the type of performance qualification activities.
• Discuss the frequency of each of the individual tests included, as well as the relationship between calibration and verification.
• Delete the section Balance Checks and integrate it into Performance Qualification.
• Simplify the definition of minimum weight and add clarifications about the tare vessel as well as examples to address frequently asked questions.
• Introduce a safety factor that addresses critical performance changes of the balance during routine usage.
• Add a Glossary to clarify the use of specific terms.
• Add Additional Information to ensure alignment of concepts and terminology.

After your one-time registration on the Pharmacopeial Forum website you can view and comment on the drafts of both chapters.