Chloroquine Phosphate Tablets
» Chloroquine Phosphate Tablets contain not less than 93.0 percent and not more than 107.0 percent of the labeled amount of C18H26ClN3·2H3PO4.
Packaging and storage Preserve in well-closed containers.
USP Reference standards 11
Identification A filtered solution of the Tablets meets the requirements of Identification tests A and B under Chloroquine Hydrochloride Injection.
B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Medium: water; 900 mL.
Apparatus 2: 100 rpm.
Time: 45 minutes.
Procedure Determine the amount of C18H26ClN3·2H3PO4 dissolved from UV absorbances at the wavelength of maximum absorbance at about 343 nm of filtered portions of the solution under test, suitably diluted with Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Chloroquine Phosphate RS in the same medium.
Tolerances Not less than 75% (Q) of the labeled amount of C18H26ClN3·2H3PO4 is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Buffer solution Weigh about 13.6 g of monobasic potassium phosphate, and dissolve in 2 L of water. Add 2.0 mL of perchloric acid, mix, and adjust with phosphoric acid to a pH of 2.5. Pass the solution through a membrane filter having a 0.45-µm porosity.
Mobile phase Prepare a mixture of Buffer solution and methanol (78:22). Make adjustments if necessary (see Chromatography 621).
Standard preparation Transfer an accurately weighed quantity of USP Chloroquine Phosphate RS to a suitable volumetric flask, and dissolve in and dilute with water to volume to obtain a solution having a known concentration of about 0.15 mg per mL of chloroquine phosphate.
Assay preparation Weigh and finely powder 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 7.5 mg of chloroquine phosphate to a 50-mL volumetric flask, and dissolve in and dilute with water to volume. Sonicate for 20 minutes. Pass a portion of about 10 mL through a 0.2-µm nylon filter, discarding the first 4 mL, and use 2 mL for the analysis.
System suitability solution Transfer an accurately weighed quantity of USP Amodiaquine Hydrochloride RS and USP Chloroquine Phosphate RS to a suitable volumetric flask, and dissolve in and dilute with water to volume to obtain a solution having known concentrations of about 0.15 mg per mL of amodiaquine hydrochloride and 0.15 mg per mL of chloroquine phosphate.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 224-nm detector and a 4.6-mm × 10-cm column that contains 5-µm packing L1. The flow rate is about 1.2 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are 1.0 for chloroquine phosphate and 1.3 for amodiaquine hydrochloride; the resolution, R, between amodiaquine hydrochloride and chloroquine phosphate is not less than 1.5; the tailing factor for both compounds is not more than 1.5; and the relative standard deviation is not more than 2.0%.
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 percent of the label claim, of chloroquine phosphate (C18H26ClN3·2H3PO4) in the portion of Tablets taken by the formula:
100(CS / CU)(rU / rS)in which 100 is the percent conversion factor; CS is the concentration, in mg per mL, of USP Chloroquine Phosphate RS in the Standard preparation; CU is the concentration, in mg per mL, of chloroquine phosphate in the Assay preparation, based on the label claim; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 2632Pharmacopeial Forum: Volume No. 34(3) Page 587