BRIEFING

 Methylene Blue. This proposal is based on the version of the monograph official as of September 1, 2023. It is proposed to revise the monograph with the following changes:

1. In the Chemical Information section:

   • Add the UNII codes for the pentahydrate form.

   • Add the chemical formulas for the pentahydrate and trihydrate forms.

   • Delete the anhydrous and monohydrate forms to align with the acceptance criteria in the Loss on Drying test.

2. Revise the solution stability requirement based on the validation data in the Assay.

3. Revise the concentration of the Standard solution and Sample solution from 1 mg/mL to 0.05 mg/mL to improve the symmetry of the methylene blue peak under the Assay. The Tailing factor requirement is updated to 0.8–1.8 accordingly.

4. Add a solution stability requirement in the Organic Impurities test based on the supporting data.

5. Delete the Standard solution in the Organic Impurities test, as it is not used for system suitability or in the calculation.

6. Replace the numerical reporting threshold in the Acceptance criteria section of the Organic Impurities test with a reference to User-Determined Reporting Thresholds 〈477〉 for user flexibility.

7. Delete the chemical name from the footnote for Azure B in Table 2 in the Organic Impurities test because this chemical name is listed under the USP Reference Standards section.

8. The reference to Tests for Specified Microorganisms 〈62〉 is proposed for deletion to improve clarity, as no related acceptance criteria in this general chapter is applicable to the article.

 (SM6: S. Ramakrishna, M. Fadadu)

 Case ID—SUB-1504