<317> ICP OES Testing for Sodium Hydroxide and Potassium Hydroxide

Type of Posting: General Chapter Prospectus
Posting Date: 17-Nov-2023
Expert Committee: Excipients Test Methods (ETM)

Proposed New Title: <317> ICP OES testing for Sodium Hydroxide and Potassium Hydroxide. 
Input Deadline: 16-Dec-2023
Suggested audience: Excipient manufacturers, users, and regulators
Estimated proposal PF: 50(2) [Mar.-Apr. 2024]

Background and objectives:
Part of USP's mission is focused on strengthening the global supply of quality medicines. A major priority and a key strategy for excipients is to be a definitive source of global quality standards, to become more flexible and iterative in creating excipient standards, to expand on current compendial approaches, and thereby advancing the understanding and control of excipient composition and variability. This proposed chapter and its approach will help allow USP to continue its relevance in establishing evolving approaches for excipient standards.

  • Sodium Hydroxide and Potassium Hydroxide monographs became part of the official compendium of USP20-NF15. Both these monographs were periodically revised. 
  • In the recent past, both these monographs were revised for assay and impurities tests in USP40-NF35. Assay and impurities tests were based on atomic absorption spectroscopy (AAS). These procedures will continue to be a part of the official monographs.
  • For the assay and impurities procedures, based on AAS , USP received multiple complaints from different stakeholders, on the challenges they faced using AAS as a technique. 
  • For this reason, USP decided to develop and validate assay and impurities procedures using an advanced and highly reliable technique called ICP-OES. USP-China lab completed the assay test method validation for s odium hydroxide, using an external laboratory. 
  • The impurities test procedure for sodium hydroxide, along with the assay and impurities tests for Potassium Hydroxide were formally validated by the USP-India lab. 
  • Based on these successful validations, USP decided to introduce these procedures in the official Sodium Hydroxide and Potassium Hydroxide monographs. 
  • Both monographs were revised with the introduction of ICP-OES based procedures for assay and impurity. The proposals were published in PF 48(6). 
  • USP received multiple comments on the proposals for Sodium Hydroxide and Potassium Hydroxide. Most of the stakeholders were positive about the inclusion of ICP-OES based procedure for assay and impurities. However, most of these stakeholders requested USP to retain the AAS based procedures and introduce ICP-OES as optional. 
  • All the comments received on both these proposals were discussed with the Simple Excipients EC. As per the SE EC suggestions, it was decided to continue with the assay and impurities procedures based on the AAS technique. It was also suggested not to include ICP-OES based procedures in these monographs. 
  • USP proposed to adopt a general chapter approach to make use of the ICP-OES based procedures for both Sodium Hydroxide and Potassium Hydroxide. The justification given to the SE EC was that the end user will have the option to use the ICP-OES technique in case it requires to do so. 
  • The SE EC was also informed that the proposed General Chapter is not anticipated to be compendially required and the end users can have an option to choose between the techniques as per their requirements. 
  • With major help from USP-India and additional help from the USP-China, both the procedures for assay and impurity were optimized and successfully validated using ICP OES. 
  • Based on the SE EC recommendation, this General Chapter proposal will be brought to the Excipient Test Method EC for discussion, once ready.  
  • This new GC will help the end user by providing an option of an advanced technique for enhanced accuracy, precision, and sensitivity. 

The general chapter is intended to be applicable for assay and impurity testing for Sodium Hydroxide and Potassium Hydroxide. 

Preliminary outline: 

  • Introduction
  • Procedure
    • Solutions preparation (including standard and sample solutions)
    • Instrumental system
    • System suitability requirements
    • Analysis

Anticipated activities: USP is requesting early input from stakeholders on this proposal of a new General Chapter, <317> ICP OES testing for Sodium Hydroxide and Potassium Hydroxide, which is planned to be published for comments in Pharmacopeial Forum. 

Contact: Devendra Chavan, Ph.D. (+91-9820871960, devendravasant.c@usp.org)