A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture.

Test solution— Transfer about 200 mg of Famotidine, accurately weighed, to a 10-mL volumetric flask, add 2 mL of methanol, and shake for 10 minutes. Add 0.1 mL of glacial acetic acid, stir until dissolved, dilute with methanol to volume, and mix.

Standard solutions— Dissolve an accurately weighed portion of USP Famotidine RS in a mixture of methanol and glacial acetic acid (100:1) to obtain Standard solution 1 having a known concentration of 0.2 mg per mL. Dilute a portion of this solution, accurately measured, with a mixture of methanol and glacial acetic acid (100:1) to obtain Standard solution 2 containing 65 µg of USP Famotidine RS per mL.

Developing solvent system: a mixture of ethyl acetate, methanol, toluene, and ammonium hydroxide (40:25:20:2).

Procedure— Separately apply 5 µL of the Test solution and 5 µL of each Standard solution to a plate, and dry under a stream of nitrogen. Proceed as directed for Thin-Layer Chromatography under Chromatography 621. Examine the plate under short-wavelength UV light, and compare the intensities of any secondary spots observed in the chromatogram of the Test solution with those of the principal spots in the chromatograms of the Standard solutions: no secondary spot from the chromatogram of the Test solution is larger in size or more intense than the principal spot obtained from Standard solution 2 (0.3%); and the sum of the intensities of the secondary spots obtained from the Test solution corresponds to not more than 1.0% (Standard solution 1).