Hydroxychloroquine Sulfate
(hye drox'' ee klor' oh kwin sul' fate).
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C18H26ClN3O·H2SO4 433.95

Ethanol, 2-[[4-[(7-chloro-4-quinolinyl)amino]pentyl]ethyl]amino-, (±)-, sulfate (1:1) (salt).
(±)-2-[[4-[(7-Chloro-4-quinolyl)amino]pentyl]ethylamino]ethanol sulfate (1:1) (salt) [747-36-4].
» Hydroxychloroquine Sulfate contains not less than 98.0 percent and not more than 102.0 percent of C18H26ClN3O·H2SO4, calculated on the dried basis.
Packaging and storage— Preserve in well-closed, light-resistant containers.
USP Reference standards 11
USP Hydroxychloroquine Sulfate RS Click to View Structure
A: Ultraviolet Absorption 197U
Solution: 10 µg per mL.
Medium: dilute hydrochloric acid (1 in 100).
C: A solution (1 in 100) responds to the tests for Sulfate 191.
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 2.0% of its weight.
Ordinary impurities 466
Test solution: 10% water in methanol.
Standard solution: 10% water in methanol.
Eluant: a mixture of alcohol, water, and ammonium hydroxide (80:16:4).
Visualization: 1.
Assay— Dissolve about 100 mg of Hydroxychloroquine Sulfate, accurately weighed, in about 5 mL of water, and dilute quantitatively and stepwise with dilute hydrochloric acid (1 in 100) to obtain a solution containing about 10 µg per mL. Similarly prepare a Standard solution of USP Hydroxychloroquine Sulfate 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 100) as the blank. Calculate the quantity, in mg, of C18H26ClN3O·H2SO4 in the portion of Hydroxychloroquine Sulfate taken by the formula:
10C(AU / AS)
in which C is the concentration, in µg per mL, of USP Hydroxychloroquine Sulfate RS in the Standard solution; and AU and AS are the absorbances of the solution of Hydroxychloroquine Sulfate and the Standard solution, respectively.
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Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientific Liaison
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
USP35–NF30 Page 3454