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 98.0percent and not more than 102.0percent 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 á181ñ,chloroform being substituted for carbon disulfide in the test.
Solution: 10µg per mL.
Medium: dilute hydrochloric acid (1in 1000).
Ratio: A343/A329,between 1.00and 1.15.
Loss on drying á731ñ Dry it at 105for 16hours:it loses not more than 2.0%of its weight.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Assay— Dissolve about 100mg of Chloroquine Phosphate,accurately weighed,in about 5mLof water,and dilute quantitatively and stepwise with dilute hydrochloric acid (1in 1000)to obtain a solution containing about 10µg 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 343nm,with a suitable spectrophotometer,using dilute hydrochloric acid (1in 1000)as the blank.Calculate the quantity,in mg,of C18H26ClN3·2H3PO4in the portion of Chloroquine Phosphate taken by the formula:
in which Cis the concentration,in µg per mL,of USP Chloroquine Phosphate RSin the Standard solution,and AUand ASare the absorbances of the solution of Chloroquine Phosphate and the Standard solution,respectively.
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 444
Phone Number:1-301-816-8394