FORTABLETS LABELED SOLELY FOR VETERINARY USE :30minutes.

Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C10H21N3O·C6H8O7dissolved as directed in the Assay,preparing test solutions by quantitatively diluting filtered portions of the solution under test with phosphate buffer (1:1)containing 62.48g of monobasic potassium phosphate in 1000mLof water.

Tolerances— Not less than 75%(Q)of the labeled amount of C10H21N3O·C6H8O7is dissolved in 45minutes.

Phosphate buffer,Mobile phase,and Chromatographic system— Proceed as directed in the Assayunder Diethylcarbamazine Citrate.

Citric acid solution— Prepare a solution of citric acid in Phosphate buffercontaining 2mg per mL.

Standard solution— Prepare a solution of USP Diethylcarbamazine Citrate RSin Phosphate bufferhaving a known concentration of about 0.003mg per mL.

Test solution— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 300mg of diethylcarbamazine citrate,to a 100-mLvolumetric flask,dilute with Phosphate bufferto volume,and mix.Filter or centrifuge,and use the clear filtrate or supernatant.

Procedure— Separately inject equal volumes (about 20µL)of the Standard solution,the Test solution,and the Citric acid solutioninto the chromatograph,record the chromatograms,and measure the responses for all the peaks.Calculate the percentage of each impurity in the portion Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Diethylcarbamazine Citrate RSin the Standard solution;riis the peak response for each impurity obtained from the Test solution,disregarding any peak having a retention time corresponding to that of the main peak in the chromatogram obtained from the Citric acid solution;and rSis the peak response obtained from the Standard solution.Not more than 0.1%of any individual impurity is found.

Phosphate buffer,Mobile phase,Standard preparation,and Chromatographic system— Proceed as directed in the Assayunder Diethylcarbamazine Citrate.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 5mg of diethylcarbamazine citrate,to a 50-mLvolumetric flask,dissolve in and dilute with Phosphate bufferto volume,and mix.

Procedure— Proceed as directed in the Assayunder Diethylcarbamazine Citrate.Calculate the quantity,in mg,of diethylcarbamazine citrate (C10H21N3O·C6H8O7)in the portion of Tablets taken by the formula: in which the terms are as defined therein.