Medium: water;900mL.

Apparatus 1: 100rpm.

Time: 45minutes.

Procedure— Determine the amount of C19H23N3O2·C4H4O4dissolved from fluorometric measurements,using 322nm as the excitation wavelength and 428nm 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 RSin the same Medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C19H23N3O2·C4H4O4is dissolved in 45minutes.

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

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

Standard stock solution— Transfer 25mg of USP Ergonovine Maleate RS,accurately weighed,to a separator,shake with 10mLof water,render the mixture alkaline to litmus with 6Nammonium hydroxide,and extract with three 10-mLportions 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 10.0mLwith 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 solutionin 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 5mg of ergonovine maleate,to a separator,shake with 10mLof water,render the mixture alkaline to litmus with 6Nammonium hydroxide,and extract with three 10-mLportions of chloroform.Evaporate the combined extracts with the aid of a stream of nitrogen,but without heat,to dryness.Dissolve the residue obtained in 2.0mLof Solvent mixture.

Procedure— Apply separately 20µLof the Test preparationand 20µLof each Standard preparationto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)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 mixtureuntil 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 UVlight.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 preparationwith those of the principal spots in the chromatograms of the Standard preparations:the sum of the intensities of secondary spots obtained from the Test preparationcorresponds to not more than 5.0%of related compounds.

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

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

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

Procedure— Proceed as directed for Procedurein the Assayunder Ergonovine Maleate Injection.Calculate the quantity,in mg,of C19H23N3O2·C4H4O4in the portion of Tablets taken by the formula: in which the terms are as defined therein.