Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Time: 30 minutes.

Mobile phase— Dissolve 2.0 g of monobasic potassium phosphate in water to make 1000 mL of solution. Prepare a mixture of this solution and acetonitrile (600:400). Degas and pass through a filter having a porosity of 0.5 µm or finer. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard solution— Prepare a solution of USP Carteolol Hydrochloride RS in water having a known concentration of about 1.1L µg per mL, L being the labeled amount, in mg, of carteolol hydrochloride per Tablet.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 252-nm detector and a 3.9-mm × 30-cm column containing packing L1. The flow rate is about 1 mL per minute. Chromatograph the Standard solution, and record the responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2%.

Procedure— Pass a portion of the solution under test through a filter having a porosity of 1 µm or finer, discarding the first 2 mL of the filtrate. Separately inject equal volumes (about 15 µL) of the Standard solution and the test solution into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the quantity, in mg, of C16H24N2O3·HC1 dissolved by the formula: in which C is the concentration, in µg per mL, of USP Carteolol Hydrochloride RS in the Standard solution, and rU and rS are the carteolol peak responses obtained from the test solution and the Standard solution; respectively.

Tolerances— Not less than 80% (Q) of the labeled amount of C16H24N2O3·HCl is dissolved in 30 minutes.

pH 6.0 buffer , Mobile phase, and Diluent—Proceed as directed in the Assay under Carteolol Hydrochloride.

Standard solution— Dissolve an accurately weighed quantity of USP Dehydrocarteolol Hydrochloride RS quantitatively in Diluent to obtain a solution having a known concentration of about 1 µg per mL.

Test solution— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 10 mg of carteolol hydrochloride, to a 100-mL volumetric flask, add about 50 mL of Diluent, and shake by mechanical means for 1 hour. Dilute with Diluent to volume, and mix. Pass about 5 mL of this solution through a filter having a 0.5-µm or finer porosity.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a fluorometric detector, with excitation at 300 nm and a 418-nm emission filter, and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 5%.

Procedure— [note—Use peak areas where peak responses are indicated.] Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the dehydrocarteolol peak responses. Calculate the percentage of dehydrocarteolol hydrochloride in the portion of Tablets taken by the formula: in which C is the concentration, in µg per mL, of USP Dehydrocarteolol Hydrochloride RS in the Standard solution; L is the labeled amount, in mg, of carteolol hydrochloride in each Tablet; WA is the average weight, in mg, of each Tablet; WT is the quantity, in mg, of the portion of Tablets taken to prepare the Test solution; and rUd and rSd are the dehydrocarteolol peak responses obtained from the Test solution and the Standard solution, respectively. Not more than 1.0% is found.

pH 6.0 buffer, Mobile phase, Diluent, Standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Carteolol Hydrochloride.

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 10 mg of carteolol hydrochloride, to a 100-mL volumetric flask. Add about 50 mL of Diluent, and shake by mechanical means for 1 hour. Add 5 mL of acetonitrile, dilute with Diluent to volume, and mix. Pass a portion of this solution through a filter having a 0.5-µm or finer porosity, discarding the first 2 mL of filtrate, and use the clear filtrate as the Assay preparation.

Procedure— [note—Use peak areas where peak responses are indicated.] Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C16H24N2O3· HCl in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Carteolol Hydrochloride RS in the Standard preparation; and rU and rS are the carteolol peak responses obtained from the Assay preparation and the Standard preparation, respectively.