Change to read:

0.1MUSP28Barium acetate buffer,pH5.0;USP28Staining reagent;andProcedure— Proceed as directed in Electrophoretic purity underChondroitin Sulfate Sodium.

Standard solution— Use the Standard solutionof middle concentration in the test for Content of chondroitin sulfate sodium.

Test solution— Prepare as directed in the test for Content of chondroitin sulfate sodium.The principal spot obtained from the Test solutionhas the same migration as the principal spot obtained from the Standard solution.

Change to read:

Medium: water;900mL.

Apparatus 2: 75rpm.

Time: 60minutes.

Cetylpyridinium chloride solution,Standard solutions,USP28and Test solution— Prepare as directed in the test for Content of chondroitin sulfate sodium under Chondroitin Sulfate Sodium.USP28

Procedure— Proceed as directed in the test forContent of chondroitin sulfate sodium,adjusting the volume of the aliquot and the concentrations of the Standard solutions,USP28if necessary.Calculate the quantity,in mg,of chondroitin sulfate sodium dissolved USP28by the formula: in which Cis the concentration,in mg per mL,of chondroitin sulfate sodium in the solution under test.

Tolerances— Not less than 75%of the labeled amount of chondroitin sulfate sodium is dissolved in 60minutes.

Change to read:

Cetylpyridinium chloride solution— Prepare a solution of cetylpyridinium chloride in water having a concentration of about 1mg per mL.

Diluent— Weigh about 297mg of monobasic potassium phosphate,492mg of dibasic potassium phosphate,and 250mg of polysorbate 80,and transfer into a 1-Lbeaker.Dissolve in approximately 900mLof water,and adjust with potassium hydroxide or phosphoric acid to a pHof 7.0±0.2.Dilute with water to 1L,and mix thoroughly.USP28

Standard solutions— Prepare as directed in the test for Content of chondroitin sulfate sodiumunder Chondroitin Sulfate Sodium.

Test solution— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 100mg of chondroitin sulfate sodium,to a 100-mLvolumetric flask,add 60mLof water,USP28and shake to suspend the powder in solution.Sonicate in a 65water bath for 20minutes.Remove from the bath,stir or shakeUSP28for 5minutes,dilute with water to volume,and centrifuge or pass through a suitable filter.USP28

Procedure— Separately transfer 5.0mLof eachStandard solutionand theTest solutionto separate titration vessels,and add about 25mLof DiluentUSP28to each.Stir until a steady reading is obtained using a phototrode to determine the endpoint turbidimetrically,either at 420,550,or 660nm.Set the instrument to zero inUSP28absorbance mode.USP28From a linear regression equation calculated using the volumes of Cetylpyridinium chloride solutionconsumed,and the mass,in mg,of USP Chondroitin Sulfate Sodium RS,determine the mass of chondroitin sulfate sodium in the aliquot of the Test solutiontaken.Calculate the amount,in mg,of chondroitin sulfate sodium in the portion of Tablets taken by the formula: in whichMis the mass of Chondroitin Sulfate Sodium in the aliquot of the Test solution.