Promazine Hydrochloride Oral Solution
» Promazine Hydrochloride Oral Solution contains not less than 95.0 percent and not more than 110.0 percent of the labeled amount of C17H20N2S·HCl.
Packaging and storage Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Promazine Hydrochloride RS.
noteThroughout 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: Dilute a volume of Oral Solution, equivalent to about 50 mg of promazine hydrochloride, with 0.01 N hydrochloric acid to 25 mL, and proceed as directed under IdentificationOrganic Nitrogenous Bases 181, beginning with Transfer the liquid to a separator: the Oral Solution meets the requirements of the test.
pH 791: between 5.0 and 5.5.
Assay [noteUse low-actinic glassware.] Transfer an accurately measured volume of Oral Solution, or a quantitative dilution of it in water, equivalent to about 10 mg of promazine hydrochloride, to a 250-mL separator. Add water to adjust the volume to about 45 mL, add 3 mL of sodium hydroxide solution (1 in 10), mix, and extract the promazine with five 25-mL portions of ether. Wash the combined ether extracts with 25 mL of water, and discard the aqueous washings. Extract the combined ether extract with one 50-mL and four 25-mL portions of 0.1 N hydrochloric acid. Filter the acid extracts through a pledget of cotton washed with 0.1 N hydrochloric acid into a 250-mL volumetric flask, dilute with the same acid to volume, and mix. Without delay, concomitantly determine the absorbances of this solution and of a Standard solution of USP Promazine Hydrochloride RS in the same medium having a known concentration of about 40 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 301 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C17H20N2S·HCl in each mL of the Oral Solution taken by the formula:
(0.25C / V)(AU / AS)in which C is the concentration, in µg per mL, of USP Promazine Hydrochloride RS in the Standard solution, V is the volume, in mL, of Oral Solution taken, and AU and AS are the absorbances from the assay solution and the Standard solution, respectively.
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