Identification—
A:
Infrared Absorption 
197K
—Prepare the test specimen as follows. Powder 1 or more Tablets, and transfer a portion of the powder, equivalent to about 50 mg of amodiaquine, to a 125-mL separator. Add 20 mL of water, and shake for 1 minute. Add 25 mL of chloroform and 1 mL of ammonium hydroxide, shake for 2 minutes, and when settled, filter the chloroform extract through cotton that previously has been rinsed with chloroform, collecting the extract in a vessel suitable for evaporation. Evaporate the chloroform, and dry the residue at 105
for 1 hour.
Dissolution 711—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
30 minutes.
Procedure—
Determine the amount of C
20H
22ClN
3O·2HCl·2H
2O dissolved from UV absorbances at the wavelength of maximum absorbance at about 342 nm on filtered portions of the solution under test, suitably diluted with water, if necessary, in comparison with a Standard solution having a known concentration of
USP Amodiaquine Hydrochloride RS in the same medium.
Tolerances—
An amount of amodiaquine hydrochloride (C20H22ClN3O·2HCl·2H2O) equivalent to not less than 75% (Q) of the labeled amount of amodiaquine (C20H22ClN3O) is dissolved in 30 minutes.
Assay—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 300 mg of amodiaquine, to a 250-mL beaker, add about 100 mL of dilute hydrochloric acid (1 in 100), and heat on a steam bath for about 15 minutes with occasional stirring. Cool the mixture to room temperature, transfer to a 200-mL volumetric flask, add dilute hydrochloric acid (1 in 100) to volume, and mix. Pipet 10 mL of the clear supernatant into a 125-mL separator. Add about 10 mL of dilute hydrochloric acid (1 in 100), and wash with 20 mL of chloroform, discarding the washing. Add 4.5 mL of 1 N sodium hydroxide, and extract with four 25-mL portions of chloroform. Extract the combined chloroform solutions with three 50-mL portions of dilute hydrochloric acid (1 in 100). Combine the acid extracts in a 200-mL volumetric flask, add dilute hydrochloric acid (1 in 100) to volume, and mix. Pipet 20 mL of this solution into a 100-mL volumetric flask, add dilute hydrochloric acid (1 in 100) to volume, and mix. Concomitantly determine the absorbances of this solution and a solution of undried
USP Amodiaquine Hydrochloride RS, in the same medium having a known concentration of about 15 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 342 nm, with a suitable spectrophotometer, using dilute hydrochloric acid (1 in 100) as the blank. Calculate the quantity, in mg, of C
20H
22ClN
3O·2HCl·2H
2O in the portion of Tablets taken by the formula:
21.68C(AU / AS),
in which
C is the concentration, in µg per mL, calculated on the anhydrous basis, of the
USP Amodiaquine Hydrochloride RS in the Standard solution; and
AU and
AS are the absorbances of the solution from the Tablets and the Standard solution, respectively. The quantity determined, multiplied by 0.7656, gives the equivalent quantity of C
20H
22ClN
3O.
