Thiethylperazine Maleate
(thye eth'' il per' a zeen mal' ee ate).
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C22H29N3S2·2C4H4O4 631.76

10H-Phenothiazine, 2-(ethylthio)-10-[3-(4-methyl-1-piperazinyl)propyl]-, (Z)-2-butenedioate (1:2).
2-(Ethylthio)-10-[3-(4-methyl-1-piperazinyl)propyl]pheno thiazine maleate (1:2) [1179-69-7].
» Thiethylperazine Maleate contains not less than 98.0 percent and not more than 101.5 percent of C22H29N3S2·2C4H4O4, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Thiethylperazine Maleate RS Click to View Structure
[note—Throughout the following procedures, protect test or assay specimens, the Reference Standard, and solutions containing them, by conducting the procedures without delay, under subdued light, or using low-actinic glassware. ]
Identification, Infrared Absorption 197K.
pH 791 Dissolve 100 mg in 100 mL of water, warming, if necessary, to effect solution: the pH of this solution is between 2.8 and 3.8.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Selenium 291 The absorbance of the solution from the Test Solution, prepared with 100 mg of Thiethylperazine Maleate and 100 mg of magnesium oxide, is not greater than one-half that from the Standard Solution (0.003%).
Chromatographic purity— [note—Conduct this test promptly without exposure to daylight and with minimum exposure to artificial light. ]
Diluting solution : a mixture of methanol and ammonium hydroxide (49:1).
Test solution— Transfer 100 mg of Thiethylperazine Maleate, accurately weighed, to a 5-mL volumetric flask. Dissolve in and dilute with Diluting solution to volume, and mix.
Standard solutions— Dissolve an accurately weighed quantity of USP Thiethylperazine Maleate RS in Diluting solution, and dilute quantitatively, and stepwise if necessary, with Diluting solution to obtain a solution having a known concentration of 20.0 mg per mL (Standard solution A). Dilute appropriate portions of this solution quantitatively with Diluting solution to obtain five Standard solutions B to F having known concentrations of 0.2, 0.1, 0.06, 0.04, and 0.02 mg per mL, respectively. The final concentrations of Standard solutions B to F represent 1%, 0.5%, 0.3%, 0.2%, and 0.1% concentration of Standard solution A, respectively.
Application volume: 5 µL.
Developing solvent system: a mixture of ether, cyclohexane, methanol, and ammonium hydroxide (25:10:5:1).
Procedure— Apply equal spots of the Test solution and Standard solutions A to F as directed in Ordinary Impurities 466. Examine the plate under short- and long-wavelength UV light, then spray the plate with Dragendorff's TS, dry the plate with a stream of nitrogen, and then spray with hydrogen peroxide TS: any secondary spot in the Test solution is not more than 0.5%, and the sum of all secondary spots is not more than 2.0%.
Assay— Dissolve about 250 mg of Thiethylperazine Maleate, accurately weighed, in 30 mL of glacial acetic acid, and warm on a steam bath to effect solution. Add 1 drop of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a blue-green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 31.59 mg of C22H29N3S2·2C4H4O4.
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Monograph Elena Gonikberg, Ph.D.
Principal Scientific Liaison
(SM32010) Monographs - Small Molecules 3
Reference Standards RS Technical Services
USP35–NF30 Page 4839