BRIEFING

 Metyrosine Capsules. This proposal is based on the version of the monograph official as of September 22, 2020. The following changes are proposed:

1. Replace Identification A with the UV spectrum agreement as obtained in the proposed Assay.

2. Add Identification B based on the retention time agreement of the major peak of the Sample solution and Standard solution, as obtained in the updated Assay.

3. Replace the UV procedure in the Assay with a liquid chromatographic procedure, which is based on validation performed using the Acclaim 120 C18 brand of column with L1packing. The typical retention time for metyrosine is about 4 min.

4. Add a liquid chromatographic procedure for the Organic Impurities test, which is based on validation performed using the Acclaim 120 C18 brand of column with L1 packing. The typical retention time for metyrosine is about 13 min.

5. Add a liquid chromatographic procedure for the Limit of Metyrosine R-Enantiomer test, which is based on validation performed using the Chiralpak-IE-3 brand of column with L131 packing. The typical retention time for the metyrosine R-enantiomer is about 10.6 min.

6. Add the storage temperature requirement to the Packaging and Storage section based on the approved manufacturer's storage conditions.

7. Update the Labeling section to be consistent with the current USP style.

8. Add USP Metyrosine R-Enantiomer RS to the USP Reference Standards section to support the proposed test for Limit of Metyrosine R-Enantiomer.

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

 (SM2: M. Tiedje, H. Ramanathan)

 Case ID—SUB-765