A: Triturate a quantity of finely powdered Tablets,equivalent to about 100mg of dyphylline,with 20mLof water,and transfer to a test tube.Add 2.0mLof 2Nsodium hydroxide and 2drops of potassium permanganate TS:a green color is produced.

B: Triturate a quantity of finely powdered Tablets,equivalent to about 100mg of guaifenesin,with 10mLof chloroform,filter,and on a watch glass evaporate 1mLof the filtrate,on a steam bath,to dryness.To the residue add 1drop of formaldehyde TSand a few drops of sulfuric acid:a deep cherry-red to purple color is produced.

C: The retention times of the major peaks in the chromatogram of the Assay preparationcorrespond to those in the chromatogram of the Standard preparation,as obtained in the Assay.

Medium: water;900mL.

Apparatus 1: 100rpm.

Time: 45minutes.

Procedure— Determine the amounts of dyphylline (C10H14N4O4)and guaifenesin (C10H14O4)dissolved,using the procedure set forth in the Assay,making any necessary modifications.

Tolerances— Not less than 75%(Q)of the labeled amounts of C10H14N4O4and C10H14O4are dissolved in 45minutes.

Mobile phase,Resolution solution,and Standard preparation— Prepare as directed in the Assayunder Dyphylline and Guaifenesin Elixir.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of guaifenesin,to a 100-mLvolumetric flask,add about 80mLof Mobile phase,sonicate for 30minutes,and shake by mechanical means for an additional 30minutes.Dilute with Mobile phaseto volume,mix,and pass through a membrane filter having a 0.45-µm or finer porosity,discarding the first 10mLof the filtrate.Transfer 5.0mLof the clear filtrate to a 50-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.

Chromatographic system— Prepare as directed in the Assayunder Dyphylline and Guaifenesin Elixir,except omit the use of the guard column.

Procedure— Proceed as directed in the Assayunder Dyphylline and Guaifenesin Elixir.Calculate the quantities,in mg,of dyphylline (C10H14N4O4)and guaifenesin (C10H14O4)in the portion of Tablets taken by the formula: in which the terms are as defined therein.