Medium: water;500mL.

Apparatus 2: 50rpm,the distance between the paddle blade and the inside bottom of the vessel being maintained at 4.5±0.2cm during the test.

Time: 30minutes.

Mobile phase— Prepare as directed in theAssay.

Standard solution— Dissolve an accurately weighed quantity of USP Ergoloid Mesylates RSin water to obtain a solution having a known concentration of about 50µg per mL.Transfer 4mLof this solution for every 0.5mg of ergoloid mesylates contained in the Tablets to a 200-mLvolumetric flask,add 1mLof 0.1Nhydrochloric acid and 100mLof water,mix,and dilute with water to volume.

Test solution— Transfer a 20-mLportion of the solution under test to a suitable container,add 100µLof 0.1Nhydrochloric acid,and mix.

Chromatographic system— Proceed as directed in theAssayexcept that the sum of the relative standard deviation values for the four ergoloid mesylates peaks for replicate injections is not more than 3.0%.

Procedure— Separately inject equal volumes (about 500µL)of theStandard solution and theTest solution into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity of ergoloid mesylates as directed in theAssay.

Tolerances— Not less than 75%(Q)of the labeled amount of ergoloid mesylates is dissolved in 30minutes.

Mobile phase— Prepare a filtered and degassed solution containing a mixture of water,acetonitrile,and triethylamine (700:300:9).Make adjustments if necessary (seeSystem Suitability underChromatography á621ñ).

Internal standard solution— Transfer about 113mg of papaverine hydrochloride to a 1-Lflask.Add a mixture of 0.01Mtartaric acid and acetonitrile (2:1)to volume,and mix.

Standard preparation— Transfer about 33mg of USP Ergoloid Mesylates RS,accurately weighed,to a 100-mLvolumetric flask.Dissolve in and dilute withInternal standard solution to volume,and mix.Use a freshly prepared solution.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 5mg of Ergoloid Mesylates,to a 50-mLcentrifuge tube.Add 15.0mLofInternal standard solution,insert the stopper into the tube,and shake for about 15minutes.Centrifuge,filter if necessary,and use the clear supernatant.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm ×15-cm column that contains packing L1.[NOTE—Use an L1column capable of handling pHvalues greater than 11.]The flow rate is about 1.5mLper minute.Chromatograph theStandard preparation,and record the peak responses as directed forProcedure:the column efficiency determined for the dihydro-b-ergocryptine mesylate peak is not less than 1000theoretical plates;the tailing factor for dihydro-b-ergocryptine mesylate is not more than 2.0;the resolution,R,between the dihydro-a-ergocryptine mesylate and dihydroergocristine mesylate is not less than 2.0;the resolution,R,between dihydroergocristine and dihydro-b-ergocryptine is not less than 2.0;and the relative standard deviation of the ratio of the sum of the four peaks to the internal standard for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 20µL)of theStandard preparation and theAssay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.The order of elution is papaverine,dihydroergocornine,dihydro-a-ergocryptine,dihydroergocristine,and dihydro-b-ergocryptine.Calculate the quantity,in mg,of ergoloid mesylates in the portion of Tablets taken by the formula: in whichCis the concentration,in mg per mL,of USP Ergoloid Mesylates RSin theStandard preparation;andRUandRSare the sums of the ratios of responses of the four major peaks to the response of the internal standard peak obtained from theAssay preparation and theStandard preparation,respectively.Calculate the percentage of each of the individual alkaloids taken by the formula: where Riis the peak response ratio of the individual alkaloid to the internal standard;(MW)iis the molecular weight of the individual alkaloid;and S[Ri(MW)i]is the summation of the products of peak response ratios and molecular weights for the four alkaloids.