U.S. PHARMACOPEIA

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Atenolol Tablets
» Atenolol Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of atenolol (C14H22N2O3).
Packaging and storage— Preserve in well-closed containers.
Identification—
A: Infrared Absorption 197K—
Test specimen— Mix a quantity of powdered Tablets, equivalent to about 100 mg of atenolol, with 15 mL of methanol, heat the mixture to 50, and shake for 5 minutes. Filter, and evaporate the filtrate on a water bath to dryness. Add 10 mL of 0.1 N hydrochloric acid to the residue, warm the solution, shake, and filter. To the filtrate add sufficient 1 N sodium hydroxide to make it alkaline, extract the solution with 10 mL of chloroform, drying the chloroform extract over anhydrous sodium sulfate. Filter the dried chloroform solution, evaporate the filtrate on a water bath to dryness, and dry the residue at 105 for 1 hour.
B: The retention time of the atenolol peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Dissolution 711—
Medium: 0.1 N acetate buffer, pH 4.6, prepared by mixing 44.9 parts (v/v) of 0.1 N sodium acetate with 55.1 parts (v/v) of 0.1 N acetic acid solution; 900 mL.
Apparatus 2: 50 rpm.
Time: 30 minutes.
Determine the amount of C14H22N2O3 dissolved by employing the following method.
Mobile phase and Chromatographic system— Proceed as directed in the Assay under Atenolol.
Standard solution— Quantitatively dissolve an accurately weighed quantity of USP Atenolol RS in Mobile phase to obtain a solution having a known concentration of about 0.01 mg per mL.
Test solution— Prepare a filtered portion of the solution under test. Quantitatively dilute an accurately measured volume of the filtrate with Mobile phase to obtain a solution estimated to contain about 0.01 mg of atenolol per mL.
Procedure— Proceed as directed in the Assay, except to inject the Test solution instead of the Assay preparation. Calculate the quantity, in mg, of C14H22N2O3 dissolved by the formula:
900CD(rU / rS),
in which C is the concentration, in mg per mL, of USP Atenolol RS in the Standard solution; D is the dilution factor involved in preparing the Test solution; and rU and rS are the atenolol peak areas obtained from the Test solution and the Standard solution, respectively.
Tolerances— Not less than 80% (Q) of the labeled amount of C14H22N2O3 is dissolved in 30 minutes.
Uniformity of dosage units 905: meet the requirements.
Residual solvents 467: meet the requirements.
(Official January 1, 2007)
Assay—
Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Atenolol.
Assay preparation— Transfer 10 Tablets to a 1000-mL volumetric flask. Add 500 mL of Mobile phase, and sonicate for about 15 minutes to disintegrate the Tablets. Dilute with Mobile phase to volume, and mix. Centrifuge a portion of this mixture, and dilute an accurately measured volume of the supernatant quantitatively with Mobile phase to obtain a solution containing about 0.01 mg of atenolol per mL.
Procedure— Separately inject equal volumes (about 10 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 atenolol (C14H22N2O3) in each Tablet taken by the formula:
C(L / D)(rU / rS),
in which C is the concentration, in mg per mL, of USP Atenolol RS in the Standard preparation; L is the labeled quantity, in mg, of atenolol in each Tablet; D is the concentration, in mg per mL, of atenolol in the Assay preparation, based on the labeled quantity per Tablet and the extent of dilution; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Staff Liaison : Andrzej Wilk, Ph.D., Senior Scientific Associate
Expert Committee : (MDCV05) Monograph Development-Cardiovascular
USP29–NF24 Page 212
Pharmacopeial Forum : Volume No. 29(1) Page 49
Phone Number : 1-301-816-8305