A: The retention time of the major peak in the chromatogram of the Test solutioncorresponds to that in the chromatogram of the Standard solution,as obtained in the test for Limit of degradation products.

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

Solution A— Prepare a filtered and degassed mixture of water and acetonitrile (3:2).

Solution B— Use filtered and degassed acetonitrile.

Mobile phase— Use variable mixtures of Solution Aand Solution Bas directed for Chromatographic system.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard solution— Dissolve accurately weighed quantities of USP Paclitaxel RSand USP Paclitaxel Related Compound B RSin acetonitrile,and dilute quantitatively,and stepwise if necessary,to obtain solutions having known concentrations of about 1.2mg per mLand 0.006mg per mL,respectively.

Test solution— Quantitatively dilute an accurately measured volume of Injection with acetonitrile to obtain a solution containing about 1.2mg of paclitaxel per mL,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 227-nm detector and a 4.6-mm ×15-cm column that contains 3-µm packing L1.The flow rate is about 1.2mLper minute.The column temperature is maintained at 35.The chromatograph is programmed as follows. Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the resolution,R,between paclitaxel related compound Band paclitaxel is not less than 1.2;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas of the analyte peaks.Calculate the percentage of each degradation product in the volume of Injection taken by the formula: in which CSis the concentration,in mg per mL,of USP Paclitaxel Related Compound B RSin the Standard solution;CUis the concentration,in mg per mL,of paclitaxel in the Test solution,based on the labeled amount of paclitaxel per mLof Injection;riis the peak area for each degradation product obtained from the Test solution;and rSis the peak area for paclitaxel related compound Bobtained from the Standard solution.In addition to not exceeding the limits stated in Table 1,not more than 0.1%of any other paclitaxel degradation product is found;and not more than 2.0%of total paclitaxel degradation products is found.

Diluent— Transfer 200µLof glacial acetic acid to a 1-liter volumetric flask containing about 500mLof methanol,mix,and dilute with methanol to volume.

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (11:9).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Paclitaxel RSin Diluentto obtain a solution having a known concentration of about 0.6mg per mL.

Assay preparation— Quantitatively dilute an accurately measured volume of Injection with Diluentto obtain a solution containing about 0.6mg of paclitaxel per mL.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 227-nm detector and a 4.0-mm ×25-cm column that contains 5-µm packing L43.The flow rate is about 1.5mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the retention time of the paclitaxel peak is between 6.0and 10.0minutes;and the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the paclitaxel peaks.Calculate the quantity,in mg,of paclitaxel (C47H51NO14)in each mLof the Injection taken by the formula: in which Lis the labeled quantity,in mg,of paclitaxel in each mLof Injection;Dis the concentration,in mg per mL,of paclitaxel in the Assay preparation,based on the labeled quantity;Cis the concentration,in mg per mL,of USP Paclitaxel RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.