A: Infrared Absorption á197Mñ.

B: The retention time of the major peak for propranolol in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

C: It responds to the tests for Chloride á191ñ.

Test solution: 40mg per mL,in water.

Mobile phase— Dissolve 0.5g of sodium dodecyl sulfate in 18mLof 0.15Mphosphoric acid,add 90mLof acetonitrile and 90mLof methanol,dilute with water to make 250mL,mix,and pass through a filter having a 0.5-µm or finer porosity.Make adjustments if necessary (seeSystem SuitabilityunderChromatography á621ñ).

Standard preparation— Quantitatively dissolve an accurately weighed quantity of USP Propranolol Hydrochloride RSin methanol to obtain a stock solution having a known concentration of about 1mg per mL.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,dilute with methanol to volume,mix,and pass through a filter having a 0.7-µm or finer porosity.This solution contains about 0.2mg of USP Propranolol Hydrochloride RSper mL.

Resolution solution— Prepare a solution of procainamide hydrochloride in methanol containing about 0.25mg per mL.Transfer 5mLof this solution and 5mLof the stock solution used to prepare theStandard preparationto a 25-mLvolumetric flask,dilute with methanol to volume,and mix.

Assay preparation— Transfer about 50mg of Propranolol Hydrochloride,accurately weighed,to a 50-mLvolumetric flask,add 45mLof methanol,shake,and sonicate for 5minutes.Dilute with methanol to volume,mix,and pass through a filter having a 0.7-µm or finer porosity.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,dilute with methanol to volume,and mix.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 290-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L7.The flow rate is about 1.5mLper minute.Chromatograph theResolution solution,and record the peak responses as directed forProcedure:the relative retention times are about 0.6for procainamide and 1.0for propranolol;and the resolution,R,between the procainamide and the propranolol peaks is not less than 2.0.Chromatograph theStandard preparation,and record the peak responses as directed forProcedure:the tailing factor for the propranolol peak is not more than 3.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of theStandard preparationand theAssay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C16H21NO2·HCl in the portion of Propranolol Hydrochloride taken by the formula: in whichCis the concentration,in mg per mL,of USP Propranolol Hydrochloride RSin theStandard preparation;andrUandrSare the propranolol peak responses obtained from theAssay preparationand theStandard preparation,respectively.