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.

A: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation obtained as directed in the Assay.

B: Triturate a portion of powdered Tablets, equivalent to about 10 mg of trimeprazine, with 10 mL of methanol, and centrifuge: 5 µL of this solution meets the requirements of Identification test C under Trimeprazine Tartrate.

Medium: 0.01 N hydrochloric acid; 500 mL.

Apparatus 1: 100 rpm.

Time: 45 minutes.

Procedure— Determine the amount of C18H22N2S dissolved by employing UV absorption at the wavelength of maximum absorbance at about 251 nm on filtered portions of the solution under test, suitably diluted with Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Trimeprazine Tartrate RS in the same Medium.

Tolerances— Not less than 75% (Q) of the labeled amount of C18H22N2S is dissolved in 45 minutes.

Procedure for content uniformity— Transfer 1 Tablet to a 100-mL volumetric flask, add about 50 mL of 0.1 N hydrochloric acid, and shake by mechanical means until the tablet is completely disintegrated. Add 0.1 N hydrochloric acid to volume, mix, and filter, discarding the first 20 mL of the filtrate. Dilute a portion of the subsequent filtrate, quantitatively and stepwise if necessary, with 0.1 N hydrochloric acid to obtain a solution having a known concentration of about 5 µg of trimeprazine per mL. Concomitantly determine the absorbances of this solution and a solution of USP Trimeprazine Tartrate RS in the same medium, having a known concentration of about 6 µg per mL, in 1-cm cells, at 276 nm and at the wavelength of maximum absorbance at about 251 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in mg, of trimeprazine in the Tablet by the formula: in which T is the labeled quantity, in mg, of trimeprazine in the Tablet, D is the concentration, in µg per mL, of trimeprazine in the test solution, based on the labeled quantity per Tablet and the extent of dilution, C is the concentration, in µg per mL, of USP Trimeprazine Tartrate RS in the Standard solution, 0.7991 is the factor converting trimeprazine tartrate to trimeprazine, and the parenthetic expressions are the differences in the absorbances of the two solutions at the wavelengths indicated by the subscripts, for the solution from the Tablets (U) and the Standard solution (S), respectively.

(Official January 1, 2007)

Mobile phase , Standard preparation, and Chromatographic system—Proceed as directed in the Assay under Trimeprazine Tartrate.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 5 mg of trimeprazine, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, mix, and filter.

Procedure— Separately inject equal volumes (about 25 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C18H22N2S in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Trimeprazine Tartrate RS in the Standard preparation, 596.89 and 746.98 are the molecular weights of trimeprazine and trimeprazine tartrate, respectively, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.