Solvent mixture,Standard preparation,and Standard dilutions— Prepare as directed in the test for Related alkaloidsunder Ergonovine Maleate.

Test preparation— Immediately prior to use,transfer a volume of Injection,equivalent to about 5mg of ergonovine maleate,to a separator,and extract with three 5-mLportions of chloroform.Discard the chloroform extracts.Render alkaline to litmus with 6Nammonium hydroxide,and extract with three 5-mLportions of chloroform.Evaporate the combined extracts with the aid of a stream of nitrogen,but without heat,to dryness.Dissolve the residue so obtained in 0.5mLof Solvent mixture.

Procedure— Proceed as directed for Procedurein the test for Related alkaloidsunder Ergonovine Maleate.

0.05M Phosphate buffer— Dissolve 6.8g of monobasic potassium phosphate in 600mLof water and adjust with phosphoric acid to a pHof 2.1.Dilute with water to 1000mL,and mix.

Mobile phase— Prepare a suitable and degassed solution of 0.05M Phosphate bufferand acetonitrile (80:20)such that the retention time is approximately 3minutes with a flow rate of 1mLper minute.

Standard preparation— Dissolve an accurately weighed quantity of USP Ergonovine Maleate RSin Mobile phase,adding sufficient water to equal 10%of the final volume,to obtain a solution having a known concentration of about 0.02mg per mL.

Assay preparation— Quantitatively dilute an accurately measured volume of the Injection,equivalent to about 2mg of ergonovine maleate,with Mobile phaseand water,if necessary,to obtain a solution having a concentration of about 0.02mg per mLin which the Injection volume plus any added water constitutes 10%of the final volume.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 312-nm detector and a 3-mm ×30-cm column that contains packing L1.Chromatograph five replicate injections of the Standard preparation,and record the peak responses as directed under Procedure:the relative standard deviation is not more than 3.0%.

Procedure— By means of a suitable sampling valve,introduce equal volumes (about 100µL)of the Assay preparationand the Standard preparationinto the chromatograph.Measure the peak responses of Ergonovine Maleate,at corresponding retention times,obtained from the Assay preparationand the Standard preparation.Calculate the quantity,in mg,of C19H23N3O2·C4H4O4in each mLof the Injection taken by the formula: in which Cis the concentration,in mg per mL,of USP Ergonovine Maleate RSin the Standard preparation,Vis the volume,in mL,of Injection taken,Dis the dilution factor,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.