Revised USP Chapter <31> and New Chapter <1331> on Volumetric Apparatus Published for Comments

In the Pharmacopeial Forum, PF 49(5), two USP chapters related to volumetric apparatus were published for comments. It is proposed to make several changes in chapter <31> Volumetric Apparatus. Furthermore, a new general chapter <1331> Use and Calibration of Volumetric Apparatus has been developed.

A chapter numbered below 1000 becomes applicable and compendially required respect where it is referenced in a monograph or another applicable general chapter numbered below 1000 or in general notices. General chapters numbered 1000 to 1999 are for informational purposes only. They are considered interpretive and are intended to provide information on, give definition to, or describe a particular subject.

Comments on both chapters can be submitted from now on until 30 November 2023. The drafts are available via the USP website access point.

USP Chapter <31> Volumetric Apparatus

The proposal is based on the version of the chapter official as of 01 November 2020. The briefing notes list a couple of changes, including the following:

• "Clarify that a calibration temperature of 27° C is also performed in other countries that have adopted that reference temperature. Temperature correction might be required when ambient temperature differs from the reference temperature. [...]
• Provide alternatives when the limits of error are not met or not suitable at the conditions of use. [...]
• Update terminology to the International Vocabulary of Metrology [...]
• Introduce considerations for piston-operated volumetric apparatus (POVA) in several paragraphs when appropriate. [...]
• For plastic volumetric apparatuses, introduce temperature correction and equilibration, as well as limits of error. [...]"

USP Chapter <1331> Use and Calibration of Volumetric Apparatus

In the briefing notes, it is stated that "this new general chapter has been developed to provide guidelines on methods validating the original calibration of volumetric apparatus described in Volumetric Apparatus <31>, their appropriate usage, and for periodic recalibrations as needed."

The chapter is structured as follows:

• Introduction
• Scope
• User considerations
• Measurement considerations
• Calibration process
• Calculations
• Glossary
• References
• Additional sources of information