Medium: dilute hydrochloric acid (1in 100);1000mL.

Apparatus 1: 100rpm.

Time: 30minutes.

Procedure— Determine the amount of C16H21NO2·HCl dissolved from UVabsorbances at the wavelength of maximum absorbance at about 289nm of 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 Propranolol Hydrochloride RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C16H21NO2·HCl is dissolved in 30minutes.

Procedure for content uniformity— Transfer 1Tablet to a 100-mLvolumetric flask,add 5mLof dilute hydrochloric acid (1in 100),and let stand,swirling occasionally,until it is disintegrated.Add about 70mLof methanol,and sonicate for about 1minute.Dilute with methanol to volume,mix,and centrifuge a portion of the solution.Dilute an aliquot of the clear solution quantitatively with methanol to provide a solution containing about 40µg of propranolol hydrochloride per mL.Concomitantly determine the absorbances of this solution and of a solution of USP Propranolol Hydrochloride RSin methanol,at a known concentration of about 40µg per mL,in 1-cm cells at the wavelength of maximum absorbance at about 290nm,with a suitable spectrophotometer,using methanol as the blank.Calculate the quantity,in mg,of C16H21NO2·HCl in the Tablet by the formula: in which Tis the labeled quantity,in mg,of propranolol hydrochloride in the Tablet,Dis the concentration,in µg per mL,of the solution from the Tablet,based on the labeled quantity per Tablet and the extent of dilution,Cis the concentration,in µg per mL,of USP Propranolol Hydrochloride RSin the Standard solution,and AUand ASare the absorbances of the solution from the Tablet and the Standard solution,respectively.

Mobile phase,Standard preparation,Resolution solution,and Chromatographic system— Prepare as directed in the Assayunder Propranolol Hydrochloride.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 50mg of propranolol hydrochloride,to a 50-mLvolumetric flask,add 40mLof methanol,shake,and sonicate for 5minutes.Dilute with methanol to volume,mix,and filter through a 0.7-µm or finer porosity filter.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,dilute with methanol to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Propranolol Hydrochloride.Calculate the quantity,in mg,of C16H21NO2·HCl in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Propranolol Hydrochloride in the Standard preparation,and rUand rSare the propranolol peak responses obtained from the Assay preparationand the Standard preparation,respectively.