Promethazine Hydrochloride Tablets
» Promethazine Hydrochloride Tablets contain not less than 95.0 percent and not more than 110.0 percent of the labeled amount of promethazine hydrochloride (C17H20N2S·HCl).
Packaging and storage Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Promethazine 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.
Identification Shake a quantity of powdered Tablets, equivalent to about 50 mg of promethazine hydrochloride, with 30 mL of chloroform, and filter into a beaker. Evaporate the chloroform, dissolve the residue in 40 mL of dilute hydrochloric acid (1 in 1000), and transfer the liquid to a separator. In a second separator, dissolve 50 mg of USP Promethazine Hydrochloride RS in 40 mL of dilute hydrochloric acid (1 in 1000). Treat each solution as follows. Add 2 mL of 1 N sodium hydroxide and 15 mL of carbon disulfide, and shake for 2 minutes. Centrifuge if necessary to clarify the lower phase, and pass through a dry filter, collecting the filtrate in a small flask provided with a glass stopper. Reduce the volume of the carbon disulfide extracts to 4 to 5 mL, and proceed as directed under IdentificationOrganic Nitrogenous Bases 181, beginning with Determine the absorption spectra.
Medium: 0.01 N hydrochloric acid; 900 mL.
Apparatus 1: 100 rpm.
Time: 45 minutes.
Procedure Determine the amount of C17H20N2S·HCl dissolved by employing UV absorption at the wavelength of maximum absorbance at about 249 nm on filtered portions of the solution under test, suitably diluted with Dissolution Medium, in comparison with a Standard solution having a known concentration of USP Promethazine Hydrochloride RS in the same Medium.
Tolerances Not less than 75% (Q) of the labeled amount of C17H20N2S·HCl is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Procedure for content uniformity Transfer 1 finely powdered Tablet to a 100-mL volumetric flask, add 50 mL of citric acid solution (1 in 100), and shake by mechanical means for 15 minutes. Dilute with citric acid solution (1 in 100) to volume, and centrifuge about 50 mL of the mixture. Dilute an accurately measured portion of the clear solution, equivalent to 5 mg of promethazine hydrochloride, quantitatively with citric acid solution (1 in 100) to 100 mL. Concomitantly determine the absorbance of this solution and a Standard solution of USP Promethazine Hydrochloride RS in the same medium, having a known concentration of about 50 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 298 nm, with a suitable spectrophotometer, using citric acid solution (1 in 100) as the blank. Calculate the quantity, in mg, of C17H20N2S·HCl in the Tablet by the formula:
(TC / D)(AU / AS)in which T is the labeled quantity, in mg, of promethazine hydrochloride in the Tablet; D is the concentration, in µg per mL, of promethazine hydrochloride 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 Promethazine Hydrochloride RS in the Standard solution; and AU and AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.
Buffered palladium chloride solution Transfer 500 mg of palladium chloride to a 250-mL beaker, add 5 mL of hydrochloric acid, and warm on a steam bath. Add 200 mL of hot water in small quantities while stirring until solution is complete. Cool, dilute with water to 500 mL, and mix. Transfer 25 mL of this solution to a 500-mL volumetric flask. Add 50 mL of 1 N sodium acetate and 48 mL of 1 N hydrochloric acid, dilute with water to volume, and mix.
Standard preparation Transfer about 31 mg of USP Promethazine Hydrochloride RS, accurately weighed, to a low-actinic 250-mL volumetric flask. Dissolve in 0.1 N hydrochloric acid, dilute with 0.1 N hydrochloric acid to volume, and mix.
Assay preparation Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 6.25 mg of promethazine hydrochloride, to a low-actinic 125-mL separator. Add 20 mL of saturated potassium chloride solution, 10 mL of 1 N sodium hydroxide, and 10 mL of methanol, and extract the promethazine with three 20-mL portions of n-heptane. Filter the heptane extracts through anhydrous sodium sulfate and collect them in a low-actinic 125-mL separator. Extract the promethazine from the n-heptane solution with three 15-mL portions of 0.1 N hydrochloric acid, collect the acid extracts in a low-actinic 50-mL volumetric flask, dilute with 0.1 N hydrochloric acid to volume, and mix.
Procedure Into separate test tubes, pipet 2-mL portions of the Standard preparation, the Assay preparation, and 0.1 N hydrochloric acid to provide a blank. Add 3.0 mL of Buffered palladium chloride solution to each tube, and mix. Concomitantly determine the absorbances of the solutions at the wavelength of maximum absorbance at about 470 nm, using a suitable spectrophotometer, and using the blank in the reference cell. Calculate the quantity, in mg, of promethazine hydrochloride (C17H20N2S·HCl) in the portion of Tablets taken by the formula:
50C(AU / AS)in which C is the concentration, in mg per mL, of USP Promethazine Hydrochloride RS in the Standard preparation; and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 3407Pharmacopeial Forum: Volume No. 32(4) Page 1107
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.