Spray reagent— Add 5.6g of stannous chloride to 10mLof hydrochloric acid,and stir for 5minutes.[NOTE—It is not necessary that all of the solids dissolve.]Add 90mLof water and 1g of potassium iodide,and stir.Prepare this solution fresh daily.

Standard solution— Prepare a solution in water containing 10mg of USP Carboplatin RSper mL.

Test solution— Dissolve the contents of 1container in water to obtain a solution containing 10mg of carboplatin per mL.

Procedure— Separately apply 10µLeach of the Standard solutionand the Test solutionto a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Place the plate in a chromatographic chamber lined with filter paper and equilibrated for 2hours with a mixture of acetone and water (80:20).Develop the chromatogram until the solvent front has moved about 10cm from the origin.Remove the plate from the chamber,and air-dry at room temperature for 2hours.Spray with the Spray reagent,and heat at 110for 10minutes:the principal spot from the Test solutioncorresponds in appearance and RFvalue to that obtained from the Standard solution.

Mobile phase ,System suitability solution,and Chromatographic system—Proceed as directed for Limit of 1,1-cyclobutanedicarboxylic acidunder Carboplatin.

Standard solution— Dissolve an accurately weighed quantity of 1,1-cyclobutanedicarboxylic acid in Mobile phaseto obtain a solution having a known concentration of about 0.5mg per mL.Transfer 2.0mLof this solution to a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.

Test solution— Quantitatively dissolve the contents of 1container in Mobile phaseto obtain a solution having a concentration of 1mg of carboplatin per mL.[NOTE—Complete the chromatographic analysis of the solution within 2hours.]

Procedure— Separately inject equal volumes (about 100µL)of the Test solutionand the Standard solutioninto the chromatograph,record the chromatograms,and measure the responses for the 1,1-cyclobutanedicarboxylic acid peaks.Calculate the percentage of 1,1-cyclobutanedicarboxylic acid in the portion of Carboplatin for Injection taken by the formula: in which Cis the concentration,in mg per mL,of 1,1-cyclobutanedicarboxylic acid in the Standard solution,Vis the volume,in mL,of the constituted container contents,Lis the labeled quantity,in mg,of carboplatin per container,and rUand rSare the peak responses for 1,1-cyclobutanedicarboxylic acid obtained from the Test solutionand the Standard solution,respectively:not more than 1.0%is found.

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

Assay preparation— Quantitatively dissolve the contents of 1container in water to obtain a solution having a concentration of 1mg per mL.[NOTE—Complete chromatographic analysis of this solution within 2hours.]

Procedure— Separately inject equal volumes (about 10µL)of the Assay preparationand the Standard preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C6H12N2O4Pt in the portion of Carboplatin for Injection taken by the formula: in which Cis the concentration,in mg per mL,of USP Carboplatin RSin the Standard preparation,Vis the volume,in mL,of the constituted container contents,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.