Chloroquine Phosphate
(klor' oh kwin fos' fate).
C18H26ClN3·2H3PO4 515.86

1,4-Pentanediamine, N4-(7-chloro-4-quinolinyl)-N1,N1-diethyl-, phosphate (1:2).
7-Chloro-4-[[4-(diethylamino)-1-methylbutyl]amino]quinoline phosphate (1:2) [50-63-5].
» Chloroquine Phosphate contains not less than 98.0 percent and not more than 102.0 percent of C18H26ClN3·2H3PO4, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
USP Reference standards 11
USP Chloroquine Phosphate RS Click to View Structure
USP Hydroxychloroquine Sulfate RS Click to View Structure
Identification—
A: It meets the requirements under Identification—Organic Nitrogenous Bases 181, chloroform being substituted for carbon disulfide in the test.
Solution: 10 µg per mL.
Medium: dilute hydrochloric acid (1 in 1000).
Ratio: A343/A329, between 1.00 and 1.15.
C: 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.
Loss on drying 731 Dry it at 105 for 16 hours: it loses not more than 2.0% of its weight.
Assay—
Buffer solution— Accurately weigh about 13.6 g of monobasic potassium phosphate, and dissolve in 2 L of water. Add 2.0 mL perchloric acid, mix, and adjust with phosphoric acid to a pH of 2.5 ± 0.5. 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 System Suitability under 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 concentration of about 0.15 mg per mL of chloroquine phosphate.
Assay preparation— Transfer an accurately weighed quantity of Chloroquine Phosphate to a suitable volumetric flask, and dissolve in and dilute with water to volume to obtain a solution having a concentration of about 0.15 mg per mL of chloroquine phosphate.
System suitability solution— Transfer accurately weighed quantities of USP Hydroxychloroquine Sulfate 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 concentrations of about 0.015 mg per mL of hydroxychloroquine sulfate and 0.15 mg per mL of chloroquine phosphate.
Chromatography 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. The column temperature is maintained at 25 ± 5. 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 0.8 for hydroxychloroquine sulfate; the resolution, R, between chloroquine phosphate and hydroxychloroquine sulfate is not less than 1.5; the column efficiency is not less than 2000 theoretical plates; for both compounds, the tailing factor is not more than 2.0; 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 percentage of C18H26ClN3·2H3PO4 in the portion of Chloroquine Phosphate 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; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientific Liaison
1-301-816-8394
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
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