BRIEFING

 Sodium Polystyrene Sulfonate Suspension. This proposal is based on the version of the monograph official prior to 2013. It is proposed to make the following changes:

1. Add a footnote for the surfactant used in both the test for Sodium Content and the test for Potassium Exchange Capacity.

2. Provide flexibility in drawing the calibration curve by removing the use of "ruled coordinate paper" in both the test for Sodium Content and the test for Potassium Exchange Capacity.

3. Provide clarity in the preparation of the Standard solutions, Sample stock solution, and Sample solution in the test for Sodium Content.

4. Correct the analysis equation in the test for Sodium Content.

5. Provide clarity in the preparation of the Standard solutions in the test for Potassium Exchange Capacity. Add a volume determination step in the Sample stock solution preparation.

6. Correct the analysis equation in the test for Potassium Exchange Capacity.

7. The references to Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉 are separated to more clearly communicate the requirements associated with each of the general chapters.

8. Add a temperature requirement based on approved product inserts in the Packaging and Storage section.

 Manufacturers are encouraged to submit their methods and FDA-approved specifications for the expert committee's consideration.

 Additionally, minor editorial changes have been made to update the monograph to current USP style.

 The comment period for this revision ends on July 31, 2025. In the absence of any significant adverse comment, it is proposed to implement this revision via an Interim Revision Announcement with an official date of November 1, 2025.

 (SM4: Y. Yang)

 Case ID—SUB-1128