Medium: 0.01Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 15minutes.

Procedure— Determine the amount of C10H16N6Sdissolved by employing UVabsorption at the wavelength of maximum absorbance at about 218nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,in comparison with a Standard solution having a known concentration of USP Cimetidine RSin the same Medium.

Tolerances— Not less than 80%(Q)of the labeled amount of C10H16N6Sis dissolved in 15minutes.

Mobile phase ,Standard preparation,and Chromatographic system—Proceed as directed in the Assayunder Cimetidine.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of Cimetidine,to a 250-mLvolumetric flask.Add 50mLof methanol,shake for 2minutes,add 40mLof water,sonicate for 15minutes,dilute with water to volume,and mix.Transfer 5.0mLof this solution to a 200-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.

Procedure— Separately inject equal volumes (about 50µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of cimetidine (C10H16N6S)in the portion of Tablets taken by the formula: in which the terms are as defined in the Assayunder Cimetidine.