Thiothixene Hydrochloride
C23H29N3O2S2·2HCl·2H2O 552.58

9H-Thioxanthene-2-sulfonamide,N,N-dimethyl-9-[3-(4-methyl-1-piperazinyl)propylidene]-,dihydrochloride,dihydrate,(Z)-.
N,N-Dimethyl-9-[3-(4-methyl-1-piperazinyl)propylidene]thioxanthene-2-sulfonamide dihydrochloride dihydrate [22189-31-7;49746-09-0].

Anhydrous 516.56 [58513-59-0;49746-04-5].
»Thiothixene Hydrochloride contains two molecules of water of hydration or is anhydrous.It contains not less than 97.0percent and not more than 102.5percent of C23H29N3O2S2·2HCl,calculated on the anhydrous basis.
Packaging and storage— Preserve in tight,light-resistant containers.
Identification—
A: It meets the requirements under Identification—Organic Nitrogenous Bases á181ñ,USP Thiothixene RSbeing used as the standard for comparison,chloroform being used instead of carbon disulfide,and a reagent blank being used in the matched reference cell.
B: Ultraviolet Absorption á197Uñ—
Solution: 10µg per mL.
Medium: dilute methanolic hydrochloric acid (1in 1200).
Absorptivities at 307nm,calculated on the anhydrous basis,do not differ by more than 3.0%.
C: Asolution (1in 100)responds to the tests for Chloride á191ñ.
Water,Method Iá921ñ: between 6.2%and 7.5%for the dihydrate;not more than 1.0%for the anhydrous form.
Residue on ignition á281ñ: not more than 0.2%.
Selenium á291ñ: 0.003%.
Limit of (E)-thiothixene— [NOTE—Prepare all solutions in low-actinic glassware.]
Mobile phase— Prepare as directed in the test for Limit of(E)-thiothixeneunder Thiothixene.
Standard preparations and Test preparation—Prepare as directed in the test for Limit of (E)-thiothixeneunder Thiothixene,except to use 250mg of Thiothixene Hydrochloride instead of 200mg of Thiothixene.
Procedure— Proceed as directed for Procedurein the test for Limit of (E)-thiothixeneunder Thiothixene.Calculate the quantity,in mg,of (E)-thiothixene hydrochloride in the portion of Thiothixene Hydrochloride taken by the formula:
5CHU(516.56/443.63)/(HC-HU),
in which 516.56and 443.63are the molecular weights of anhydrous thiothixene hydrochloride and thiothixene,respectively;and the other terms are as previously defined.The limit of (E)-thiothixene,as the hydrochloride,is 1.0%.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Assay— [NOTE—Perform the dilution operations in low-actinic glassware.]
Mobile phase ,Standard preparation,and Chromatographic system—Prepare as directed in the Assayunder Thiothixene.
Assay preparation— Transfer about 116mg of Thiothixene Hydrochloride,accurately weighed,to a 100-mLvolumetric flask,dissolve in and dilute with methanol to volume,and mix.Pipet 2mLof this solution into a 100-mLvolumetric flask,dilute with methanol to volume,and mix.
Procedure— Proceed as directed for Procedurein the Assayunder Thiothixene.Calculate the quantity,in mg,of C23H29N3O2S2·2HCl in the portion of Thiothixene Hydrochloride taken by the formula:
(516.56/443.64)(5000C)(rU/rS),
in which 516.56and 443.64are the molecular weights of anhydrous thiothixene hydrochloride and thiothixene,respectively;Cis the concentration,in mg per mL,of USP Thiothixene RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1921
Pharmacopeial Forum:Volume No.29(6)Page 1993
Phone Number:1-301-816-8330