BRIEFING

 Atenolol and Chlorthalidone Tablets. This proposal is based on the version of the monograph official prior to 2013. It is proposed to revise the monograph with the following changes:

1. Replace the use of thin-layer chromatography in Identification A with the UV spectrum agreement of the major peaks of the Sample solution and the Standard solution, as obtained in the Assay.

2. In the Assay:

   • Clarify the Sample solution concentration.

   • Add the Run time.

   • Revise the Chromatographic system to include the information for diode array detection needed to support the proposed Identification A and to add the particle size for the Column.

   • Add clarification to the Relative standard deviation requirement in the Suitability requirements by identifying the specific analytes of atenolol and chlorthalidone.

   • Revise the %RSD value from 2.0% to 1.0% for atenolol and chlorthalidone based on supporting data.

3. Delete the Procedure for content uniformity from the Uniformity of Dosage Units test to allow for flexibility in using manufacturers' approved procedures.

4. Add a validated stability-indicating HPLC procedure for the Organic Impurities test. The HPLC procedure is based on analyses performed with the Inertsil ODS-3V brand of column with L1 packing. The typical retention times for atenolol and chlorthalidone are about 5.7 and 30.4 min, respectively.

5. Add USP Atenolol Related Compound A RS, USP Atenolol Related Compound B RS, USP Atenolol Related Compound G RS, and USP Chlorthalidone Related Compound A RS to the USP Reference Standards section to support the proposed test for Organic Impurities.

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

 (SM2: M. Tiedje, S. Singireddy)

 Correspondence Numbers—C220513, C261076