B:
[NOTEConduct this test without exposure to daylight, and with the minimum exposure to artificial light.
] In a suitable chromatographic chamber, arranged for thin-layer chromatography (see
Chromatography 621), place a volume of a solvent system consisting of a mixture of chloroform and methanol (20:1) sufficient to develop the chromatogram. Place a beaker containing 25 mL of ammonium hydroxide in the chamber, cover, and allow to equilibrate for 30 minutes. Prepare a test solution of Methysergide Maleate in methanol containing 5 mg per mL. Apply 25 µL of this solution and 25 µL of a Standard solution of
USP Methysergide Maleate RS in methanol containing 5 mg per mL to a suitable thin-layer chromatographic plate (see
Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Develop the chromatogram 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. Locate the spots on the plate by lightly spraying with a solution prepared by dissolving 800 mg of
p-dimethylaminobenzaldehyde in a cooled mixture of 80 mL of alcohol and 20 mL of sulfuric acid, allow the plate to dry, then expose it briefly to fumes of a mixture of nitric and hydrochloric acids: the
RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.