USP Chapter 41 weighing requirements

USP Chapter 41 Weighing Requirements

Weighing in Pharmaceutical Quality Control According to U.S. Pharmacopeia Guidelines

Routine Testing of Laboratory Balances

Routine Testing of Balances and Scales Guide

How to Ensure Accurate Weighing Results Every Day? Put Routine Balance Testing into Practice

SOP for Testing Laboratory Balance

Standard Operating Procedures (SOPs) for Balance and Scale Testing

Recommendations on Balance Sensitivity, Eccentricity and Repeatability Testing

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Consistent Weighing Results with Calibration

Consistent Weighing Results with Calibration

Only regular calibration lets you know how accurate your weighing results actually are. Read more

Your Individual Routine Testing Plan

Your Individual Routine Testing Plan

Get your routine testing plan, including test frequency, methods, weights and tolerances. Read more

What is Good Weighing Practice™?

What is Good Weighing Practice™?

GWP® helps to ensure consistent quality, reduced costs and full compliance in any weighing process. Read more

1. Who needs to comply with USP 41 and Ph. Eur. 2.1.7?

Ph. Eur. 2.1.7 applies to quality control of drugs in European countries. It is also binding for pharmaceutical companies in other regions of the world who intend to export to the European market. USP 41 applies to quality control of drugs in the US. It is also binding for pharmaceutical companies in other regions of the world who intend to export to the US.

2. How does the (Accuracy Calibration Certificate) ACC fulfill the calibration requirements of Ph. Eur. Chapter 2.1.7.?

Typically, a calibration certificate indicates measurements for repeatability, eccentricity and error of indication. The ACC provides results for all these parameters, including:

  • Measurement uncertainty
  • As Found/As Left performance of the weighing instrument

The ACC indicates the measurement uncertainty for error of indication test points. Indication of measurement uncertainty in a calibration certificate is stipulated by Ph. Eur. General Chapter 2.1.7. In addition, the ACC always indicates the As Found/As Left test results in compliance with General Chapter 2.1.7.

Note that ACC does not provide the specific assessments for precision and accuracy including a statement of compliance with Ph. Eur. General Chapter 2.1.7. This is covered by the Certificate Ph. Eur. General Chapter 2.1.7.

3. Does General Chapter 2.1.7. affect only analytical balances or balances used for analytical purposes in general?

There is an official definition: An analytical balance starts with a readability of 0.1 mg or smaller.

However, the framework of the pharmacopoeia regulations considers devices that are used for analytical purposes. If you use a precision balance for analytical purposes (which is rare but might occur) then the precision balance would also have to follow USP and European Pharmacopoeia regulations.

4. How often do I have to perform the performance checks (according to Ph. Eur. 2.1.7.)?

General Chapter 2.1.7 stipulates that specific performance checks must be carried out in-between calibrations. While calibrations are usually performed annually or in intervals of three to six months, performance checks are typically performed more often, depending on the risk of the application and the quality requirements of the user. However, it is still left up to each company to define appropriate intervals for calibration and performance checks based on their own quality considerations and the risk of their specific applications. GWP® Verification fills this gap and provides a clear risk-based test strategy for suggested calibration frequencies, the individual routine tests, test weights, test weight classes, and test weight recalibration intervals.