Chloroquine Sulfate Tablets

General Notices

Chloroquine Sulphate Tablets

Action and use

Antiprotozoal (malaria).

Definition

Chloroquine Sulfate Tablets contain Chloroquine Sulfate. They are coated.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of chloroquine sulfate, C18H26ClN3,H2SO4,H2O

92.5 to 107.5% of the stated amount.

Identification

A. Dissolve a quantity of the powdered tablets containing 0.1 g of Chloroquine Sulfate in a mixture of 10 mL of water and 2 mL of 2m sodium hydroxide and extract with two 20-mL quantities of chloroform. Wash the chloroform extracts with water, dry with anhydrous sodium sulfate, evaporate to dryness and dissolve the residue in 2 mL of chloroform IR. The infrared absorption spectrum of the resulting solution, Appendix II A, is concordant with the reference spectrum of chloroquine (RS 054).
B. Shake a quantity of the powdered tablets containing 0.1 g of Chloroquine Sulfate with 10 mL of water and 1 mL of 2m hydrochloric acid and filter. To the filtrate add 1 mL of barium chloride solution. A white precipitate is produced.

TESTS

Dissolution

Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.

test conditions
(a) Use Apparatus 1, rotating the basket at 100 revolutions per minute.
(b) Use 900 mL of 0.1m hydrochloric acid, at a temperature of 37°, as the medium.
procedure
(1) After 45 minutes withdraw a 10 mL sample of the medium and measure the absorbance of a layer of suitable thickness of the filtered sample, suitably diluted with the dissolution medium if necessary, at the maximum at 344 nm, Appendix II B using 0.01m hydrochloric acid in the reference cell.
determination of content

Calculate the total content of chloroquine sulfate, C18H26ClN3,H2SO4,H2O, in the medium taking 450 as the value of A(1%, 1 cm) at the maximum at 344 nm.

Related substances

Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.

(1) Shake a quantity of the powdered tablets containing 2.0 g of Chloroquine Sulfate with 50 mL of water for 30 minutes, centrifuge and use the supernatant liquid; if necessary filter through a glass fibre paper.
(2) Dilute 1 mL of solution (1) to 100 mL with water.
(3) Dilute 25 mL of solution (2) to 50 mL with water.
chromatographic conditions
(a) Use as the coating silica gel GF254.
(b) Use the mobile phase as described below.
(c) Apply 2 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry in air and examine under ultraviolet light (254 nm).
mobile phase

10 volumes of diethylamine, 40 volumes of cyclohexane and 50 volumes of chloroform.

limits

Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) and not more than one such spot is more intense than the spot in the chromatogram obtained with solution (3).

Assay

Weigh and powder 20 tablets. Dissolve a quantity of the powder containing 0.5 g of Chloroquine Sulfate in 20 mL of 1m sodium hydroxide and extract with four 25-mL quantities of chloroform. Combine the chloroform extracts and evaporate to a volume of about 10 mL. Add 40 mL of anhydrous acetic acid and carry out Method I for non-aqueous titration, Appendix VIII A, determining the end point potentiometrically. Each mL of 0.1m perchloric acid VS is equivalent to 20.90 mg of C18H26ClN3,H2SO4.

200 mg of Chloroquine Sulfate is approximately equivalent to 146 mg of chloroquine.