Identification
A:
The IR absorption spectrum of a potassium bromide dispersion of it, previously dried, exhibits maxima only at the same wavelengths as that of a similar preparation of
USP Levamisole Hydrochloride RS.
B:
The color, size, and
RF value of the principal spot in the chromatogram of
Test solution B obtained in the test for
Chromatographic purity, when examined under short-wavelength UV light, correspond to the respective characteristics of the principal spot in the chromatogram of
Reference solution A obtained in the test for
Chromatographic purity.
C:
A solution of it responds to the tests for
Chloride 191.
Chromatographic purity
Prepare a solution of it in methanol containing 50 mg per mL (
Test solution A). Dilute 1.0 mL of
Test solution A to 10 mL with methanol, and mix (
Test solution B). Prepare a solution of
USP Levamisole Hydrochloride RS in methanol having a concentration of 5 mg per mL (
Reference solution A). Dilute 1.0 mL of
Test solution B to 20 mL with methanol, and mix (
Reference solution B). Apply separate 10-µL portions of the four solutions on the starting line to a suitable thin-layer chromatographic plate (see
Chromatography 621), coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of toluene, acetone, and ammonium hydroxide (60:40:1) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, and dry it at 105
for 15 minutes. Locate the spots on the plate by examination under short-wavelength UV light: any spot obtained from
Test solution A, other than the one corresponding to levamisole, does not exceed, in size or intensity, the principal spot obtained from
Reference solution B, corresponding to not more than 0.5% of any individual impurity. Expose the plate to iodine vapor in a closed chamber for 15 minutes, and locate the spots on the plate: any spot obtained from
Test solution A, other than the one corresponding to levamisole, does not exceed, in size or intensity, the principal spot obtained from
Reference solution B, corresponding to not more than 0.5% of any individual impurity, and the total of all impurities found does not exceed 1.0%.