443.62
9H-Thioxanthene-2-sulfonamide, N,N-dimethyl-9-[3-(4-methyl-1-piperazinyl)propylidene]-, (Z)-;
N,N-Dimethyl-9-[3-(4-methyl-1-piperazinyl)propylidene]thioxanthene-2-sulfonamide
(Z)-N,N-Dimethyl-9-[3-(4-methylpiperazin-1-yl)propylidene]-9H-thioxanthene-2-sulfonamide [5591-45-7] [3313-26-6]
BRIEFING
Thiothixene. This proposal is based on the version of the monograph official as of June 1, 2023. It is proposed to revise the monograph with the following changes.
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In the Chemical Information section, update the molecular weight and chemical name of Thiothixene to be consistent with the current USP naming convention. Add the UNII code for Thiothixene. Remove the CAS number of the nonstereospecific molecule.
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Replace 197S in Identification A with 197A or 197K. This revision avoids the use of a toxic solvent in the preparation of the sample.
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Replace 197U in Identification B with the retention time agreement of the major peak of the Sample solution and the Standard solution, as obtained in the proposed Assay.
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Replace the LC procedures in the Assay and test for the Limit of (E)-Thiothixene with an LC procedure for the Assay and test for Organic Impurities that was validated using the XBridge BEH Shield RP18 brand of column with L1 packing. The typical retention time for thiothixene is about 4.7 min.
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Remove the test for Selenium from this monograph because this elemental impurity will be controlled in the drug product using the risk-based approach specified in Elemental Impurities—Limits 〈232〉. The risk-based approach will be used to determine the presence of an elemental impurity (in components of the formulation or in the drug product) and the appropriate level of control. Therefore, it is redundant to include the test and Acceptance criteria for the elemental impurity selenium in this monograph.
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Remove the nonspecific Melting Range or Temperature test because other tests in the monograph can adequately monitor the quality of the drug substance.
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In the USP Reference Standards section, add the chemical information of USP (E)-Thiothixene RS. Add USP Thiothixene Related Compound A RS and related chemical information to support the proposed test for Organic Impurities.
Stakeholders are encouraged to submit their FDA-approved specifications, if different from the proposed ones, to USP for consideration.
Additionally, minor editorial changes have been made to update the monograph to current USP style.
(SM4: S. Singireddy)
Case ID—SUB-1303, SUB-1318
USP REFERENCE STANDARDS FOR PURCHASE
USP (E)-Thiothixene RSUSP Thiothixene RS
USP Thiothixene Related Compound A RS