note—Throughout the following procedures, protect test or assay specimens, the USP Reference Standard, and solutions containing them, by conducting the procedures without delay, under subdued light, or using low-actinic glassware.

A: Transfer about 1.0 mL of Oral Suspension, accurately weighed, to a glass-stoppered, low-actinic 35-mL centrifuge tube; add 10.0 mL of methanol; and shake vigorously by mechanical means for 3 minutes. Centrifuge for 5 minutes, and use the methanol layer for the test. Apply 50 µL of the test solution in streaks 4 to 5 cm in length and 0.2 cm in width and 50 µL of a Standard solution containing 1 mg of USP Triflupromazine Hydrochloride RS per mL of methanol to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Allow the streaks to dry, and develop the chromatogram in a solvent system consisting of a mixture of chloroform and methanol (4:1) until the solvent front has moved about four-fifths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate. Locate the streaks by viewing the plate under short-wavelength and long-wavelength UV light: the RF value and fluorescence of the streak obtained from the test solution correspond to those obtained from the Standard solution.

B: The UV absorption spectrum of the solution employed for measurement of absorbance in the Assay exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Triflupromazine Hydrochloride RS, concomitantly measured.

for oral suspension packaged in single-unit containers: meets the requirements.

for oral suspension packaged in multiple-unit containers: meets the requirements.

Mixed solvent— Mix 25 mL of isoamyl alcohol with 10 mL of sodium hydroxide solution (1 in 25) in a separator, shake, and discard the aqueous washing. Add 10 mL of 0.1 N hydrochloric acid, shake, and discard the aqueous washing. Prepare 500 mL of a 3 in 100 solution of the washed isoamyl alcohol in n-heptane.

pH 5.6 Acetate buffer— Dissolve 1.4 g of sodium acetate in 100 mL of water, and adjust by the addition of glacial acetic acid to a pH of 5.6 ± 0.1.

Procedure— Transfer an accurately measured volume of well-mixed Oral Suspension, equivalent to about 20 mg of triflupromazine hydrochloride, to a glass-stoppered, 150-mL centrifuge bottle. In a second, similar bottle dissolve about 20 mg of USP Triflupromazine Hydrochloride RS, accurately weighed, in 1.0 mL of water; then add 1.0 mL of sodium hydroxide solution (1 in 25); and mix. To a third, similar bottle add 2 mL of water to provide the blank. Treat the two preparations and the blank as follows. Add 100.0 mL of ether, shake by mechanical means for 15 minutes, and allow the layers to separate. Transfer 50.0 mL of the ether layer to another glass-stoppered, 150-mL centrifuge bottle, and evaporate on a water bath maintained at about 35, with the aid of a current of air, to dryness. Add 5.0 mL of sodium hydroxide solution (1 in 50), mix, add 100.0 mL of Mixed solvent, shake by mechanical means for 10 minutes, and centrifuge. Transfer 20.0 mL of the nonaqueous phase to a glass-stoppered centrifuge tube, add 10.0 mL of pH 5.6 Acetate buffer, shake by mechanical means for 5 minutes, and centrifuge. Transfer 2.0 mL of the nonaqueous phase to a glass-stoppered centrifuge tube containing 25.0 mL of 0.5 N sulfuric acid, shake by mechanical means for 5 minutes, and centrifuge. Concomitantly determine the absorbances of the aqueous solutions in 1-cm cells at the wavelength of maximum absorbance at about 255 nm, with a suitable spectrophotometer, using the blank to set the instrument. Calculate the quantity, in mg, of triflupromazine hydrochloride (C18H19F3N2S·HCl) equivalent to the triflupromazine (C18H19F3N2S) in each mL of the Oral Suspension taken by the formula: in which W is the weight, in mg, of USP Triflupromazine Hydrochloride RS taken; V is the volume, in mL, of Oral Suspension taken; and AU and AS are the absorbances of the solution from the Oral Suspension and the Standard solution, respectively.