A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

C: The RF value of the principal blue spot obtained from the Test preparation corresponds to that obtained from the Standard preparation in the chromatogram prepared as directed in the test for Related alkaloids.

Test solution: 5 mg per mL, in water.

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

Solvent mixture— Prepare a mixture of alcohol and ammonium hydroxide (9:1).

Standard preparation— Prepare a solution of USP Ergonovine Maleate RS in Solvent mixture having a known concentration of about 10 mg per mL.

Standard dilutions— Prepare a series of dilutions of the Standard preparation in Solvent mixture having known concentrations of about 0.20, 0.10, and 0.05 mg per mL. Use immediately after preparation.

Test preparation— Immediately prior to use, prepare a solution of Ergonovine Maleate in Solvent mixture having a concentration of about 10 mg per mL.

Application volume: 5 µL.

Developing solvent system: a mixture of chloroform, methanol, and water (75:25:3), equilibrated for 30 minutes.

Procedure— Apply 5-µL portions of the Standard preparation, each of the three Standard dilutions, and the Test preparation, and proceed as directed for Thin-Layer Chromatography under Chromatography 621. Locate the spots on the plate by spraying thoroughly and evenly with a solution prepared by dissolving 1 g of p-dimethylaminobenzaldehyde in a cooled mixture of 50 mL of alcohol and 50 mL of hydrochloric acid. Immediately dry in a stream of nitrogen for about 2 minutes: the RF value of the principal spot obtained from the Test preparation corresponds to that obtained from the Standard preparation. Estimate the concentration of any other spots observed in the chromatogram of the Test preparation by comparison with the Standard dilutions. The spots from the 0.20, 0.10, and 0.05 mg per mL dilutions are equivalent to 2.0%, 1.0%, and 0.50% of impurities, respectively. The sum of the impurities is not greater than 2.0%.

Standard preparation— Using a suitable quantity of USP Ergonovine Maleate RS, accurately weighed, prepare a solution in water having a known concentration of about 40 µg per mL.

Assay preparation— Transfer about 40 mg of Ergonovine Maleate, accurately weighed, to a 100-mL volumetric flask, dilute with water to volume, and mix. Dilute 10.0 mL of this solution with water to 100.0 mL.

Procedure— Transfer 5.0 mL each of the Standard preparation, the Assay preparation, and water to provide a blank, to separate conical flasks. Add 10.0 mL of p-dimethylaminobenzaldehyde TS with constant swirling to each, and allow to stand for 20 minutes. Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 555 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C19H23N3O2·C4H4O4 taken by the formula: in which C is the concentration, in µg per mL, of USP Ergonovine Maleate RS in the Standard preparation, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.