Medium: water; 900 mL.

Apparatus 1: 100 rpm.

Time: 45 minutes.

Procedure— Determine the amount of C19H23N3O2·C4H4O4 dissolved from fluorometric measurements, using 322 nm as the excitation wavelength and 428 nm as the emission wavelength, of filtered portions of the solution under test, suitably diluted with Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Ergonovine Maleate RS in the same Medium.

Tolerances— Not less than 75% (Q) of the labeled amount of C19H23N3O2·C4H4O4 is dissolved in 45 minutes.

Solvent mixture— Mix 75 volumes of chloroform, 25 volumes of methanol, and 1 volume of ammonium hydroxide.

Detecting reagent— Cautiously dissolve 800 mg of p-dimethylaminobenzaldehyde in a mixture of alcohol and sulfuric acid (101:11).

Standard stock solution— Transfer 25 mg of USP Ergonovine Maleate RS, accurately weighed, to a separator, shake with 10 mL of water, render the mixture alkaline to litmus with 6 N ammonium hydroxide, and extract with three 10-mL portions of chloroform. Evaporate the combined extracts with the aid of a stream of nitrogen, but without heat, to dryness. Dissolve and dilute the residue to 10.0 mL with the Solvent mixture.

Standard preparations A , B, C, and D—Dilute accurately measured volumes of Standard stock solution quantitatively with Solvent mixture (designated below as parts by volume of Standard stock solution in total parts by volume of the finished Standard preparation) to obtain Standard preparations, designated below by letter, having the following compositions:

Test preparation— Immediately prior to use, transfer a quantity of finely powdered Tablets, equivalent to about 5 mg of ergonovine maleate, to a separator, shake with 10 mL of water, render the mixture alkaline to litmus with 6 N ammonium hydroxide, and extract with three 10-mL portions of chloroform. Evaporate the combined extracts with the aid of a stream of nitrogen, but without heat, to dryness. Dissolve the residue obtained in 2.0 mL of Solvent mixture.

Procedure— Apply separately 20 µL of the Test preparation and 20 µL of each Standard preparation to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Dry the plate with the aid of a current of cool air. Position the plate in a chromatographic chamber, and develop the chromatograms in Solvent mixture 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 in a current of cool air. Examine the plate under long-wavelength UV light. Mark the principal and any secondary fluorescent spots. Spray the plate with Detecting reagent, and mark the principal and secondary blue spots. Compare the intensities of any secondary spots observed in the chromatogram of the Test preparation with those of the principal spots in the chromatograms of the Standard preparations: the sum of the intensities of secondary spots obtained from the Test preparation corresponds to not more than 5.0% of related compounds.

(Official January 1, 2007)

0.05 M Phosphate buffer, Mobile phase, and Chromatographic system— Proceed as directed in the Assay under Ergonovine Maleate Injection.

Standard preparation— Dissolve an accurately weighed quantity of USP Ergonovine Maleate RS in Mobile phase to obtain a solution having a known concentration of about 0.02 mg per mL.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 1 mg of ergonovine maleate, to a 50-mL volumetric flask, add 25 mL of Mobile phase, place in a sonic bath for 5 minutes, cool to room temperature, dilute with Mobile phase to volume, mix, and centrifuge. Use the supernatant as directed in the Procedure.

Procedure— Proceed as directed for Procedure in the Assay under Ergonovine Maleate Injection. Calculate the quantity, in mg, of C19H23N3O2·C4H4O4 in the portion of Tablets taken by the formula: in which the terms are as defined therein.