BRIEFING

 Levocarnitine. This proposal is based on the version of the monograph official as of December 1, 2021. On the basis of comments received, the proposal in PF 49(2) has been canceled and the following changes are being proposed:

1. Replace the titration-based method for the Assay with a new HPLC-UV method, which replaces the one proposed in PF 49(2). This new method is based on analysis performed with the Waters Spherisorb SCX brand of column with L9 packing. The typical retention times of the cis- and trans-crotonobetaine (isomers of levocarnitine related compound A), and levocarnitine are 10.2, 11.2, and 12.8 min, respectively.

2. Replace Identification B with a new procedure that uses the retention time of levocarnitine as shown in the new Assay.

3. Add the Related Compounds test that is adopted from the method proposed for the Assay.

4. Replace the derivatization HPLC-based method used in the Enantiomeric Purity test with a direct chiral HPLC method that is based on analysis performed with the Supelco Astec Chirobiotic TAG brand of column with L63 packing. The typical retention times of levocarnitine, d-carnitine, and levocarnitine related compound A are 13.6, 15.9, and 18.6 min, respectively.

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

 (NBDS: F. Tadjimukhamedov)

 Case ID—SUB-2312