A: Infrared Absorption á197Mñ.

B: The RFvalue of the principal spot in the chromatogram of the Identification corresponds to that of Standard preparation Aas obtained in the test for Chromatographic purity.

Standard solutions— Dissolve USP Antazoline Phosphate RSin methanol,and mix to obtain a solution having a known concentration of 0.10mg per mL.Quantitatively dilute with methanol to obtain 5Standard solutionshaving the following compositions:

Test solution— Dissolve an accurately weighed quantity of Antazoline Phosphate in methanol to obtain a solution containing 10mg per mL.

Identification solution— Dilute a portion of the Test solutionquantitatively with methanol to obtain a solution containing 50µg per mL.

Procedure— Apply separately 10µLof the Test solution,10µLof the Identification solution,and 10µLof each Standard solutionto a suitable thin-layer chromatographic plate (see Chromatography á621ñ),coated with a 0.25-mm layer of chromatographic silica gel mixture.Position the plate in a chromatographic chamber,and develop the chromatograms in a solvent system consisting of a mixture of ethyl acetate,methanol,and diethylamine (17:2:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Examine the plate under short-wavelength UVlight,and compare the intensities of any secondary spots observed in the chromatogram of the Test solutionwith those of the principal spots in the chromatograms of the Standard solutions.[NOTE—Disregard any spots observed at the origins of the chromatograms.]No secondary spot from the chromatogram of the Test solutionis larger or more intense than the principal spot obtained from Standard solution A(0.5%),and the sum of the intensities of all secondary spots obtained from the Test solutioncorresponds to not more than 1.0%.