Identification
Solution:
10µg per mL.
Medium:
dilute hydrochloric acid (1in 1000).
Ratio:
A343/A329,between 1.00and 1.15.
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 C
18H
26ClN
3·2H
3PO
4in the portion of Chloroquine Phosphate taken by the formula:
10C(AU/AS),
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.