Chloroquine Phosphate
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.
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.
Loss on drying 731 Dry it at 105 for 16 hours: it loses not more than 2.0% of its weight.
Assay— Dissolve about 100 mg of Chloroquine Phosphate, accurately weighed, in about 5 mL of water, and dilute quantitatively and stepwise with dilute hydrochloric acid (1 in 1000) to obtain a solution containing about 10 µg per mL. Similarly prepare a Standard solution of USP Chloroquine Phosphate RS. Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 343 nm, with a suitable spectrophotometer, using dilute hydrochloric acid (1 in 1000) as the blank. Calculate the quantity, in mg, of C18H26ClN3·2H3PO4 in the portion of Chloroquine Phosphate taken by the formula:
10C(AU / AS)
in which C is the concentration, in µg per mL, of USP Chloroquine Phosphate RS in the Standard solution; and AU and AS are the absorbances of the solution of Chloroquine Phosphate and the Standard solution, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 1903
Pharmacopeial Forum: Volume No. 34(2) Page 251
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.