A: Infrared Absorption á197Kñ.

B: It meets the requirements of the tests for Chloride á191ñ.

Test solution: 10mg per mL.

Solution A— Proceed as directed for Mobile phasein the Assay.

Solution B— Prepare filtered and degassed methanol.

Mobile phase— Use variable mixtures of Solution Aand Solution Bas directed under Chromatographic system.Make adjustments,if necessary (see System SuitabilityunderChromatography á621ñ).

System suitability solution— Proceed as directed in the Assay.

Standard solution— Dissolve an accurately weighed quantity of USP Gemcitabine Hydrochloride RSand USP Cytosine RSin water,and dilute quantitatively,and stepwise if necessary,to obtain a solution having a known concentration of about 2µg per mLof each.

Test solution— Transfer about 50mg of Gemcitabine Hydrochloride,accurately weighed,to a 25-mLvolumetric flask,dissolve in and dilute with water to volume,and mix.

Chromatographic system (see Chromatography á621ñ)— Proceed as directed under Assay.The chromatograph is programmed as follows. Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.5for gemcitabine a-anomer and 1.0for gemcitabine;the resolution,R,between gemcitabine a-anomer and gemcitabine is not less than 8.0;and the tailing factor for gemcitabine is not more than 1.5.Chromatograph the standard solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.1for cytosine and 1.0for gemcitabine;the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject a volume (about 20µL)of the Standard solutionand Test solutioninto the chromatograph,record the chromatogram,and measure all of the peak responses.Calculate the percentage of cytosine in the portion of Gemcitabine taken by the formula: in which Ccis the concentration of USP Cytosine RSin the Standard solution,in µg per mL;Wis the weight,in mg,of Gemcitabine taken;rtis the peak response for cytosine in the Test solution;and rsis the response for cytosine in theStandard solution:not more than 0.1%of cytosine is found.Calculate the percentage of each impurity other than cytosine in the portion of Gemcitabine taken by the formula: in which Csis the concentration of USP Gemcitabine Hydrochloride RSin the Standard solution,in µg per mL;Wis the weight,in mg,of Gemcitabine taken;riis the peak response for each impurity in the Test solution;and rsis the response due to gemcitabine in the Standard solution:not more than 0.1%of gemcitabine a-anomer or any other individual impurity is found;and the sum of all impurities is not more than 0.2%.Exclude from the sum of all impurities any peaks that are below the limit of quantitation (0.02%).

Mobile phase— Prepare a filtered and degassed solution containing 13.8g of monobasic sodium phosphate and 2.5mLof phosphoric acid in 1000mLof water.[NOTE—The pHof this solution is between 2.4and 2.6.]

System suitability solution— Transfer about 10mg of Gemcitabine Hydrochloride to a small vial,add 4mLof a solution containing 168mg of potassium hydroxide per mLof methanol,cap tightly,and sonicate.Heat at 55for 6to 16hours,allow to cool,and transfer the contents to a 100-mLvolumetric flask with successive washes of 1%(v/v)phosphoric acid.Dilute with 1%phosphoric acid to volume,and mix.[NOTE—This solution contains about 0.02mg per mLof gemcitabine a-anomer.]

Standard preparation— Dissolve an accurately weighed quantity of USP Gemcitabine Hydrochloride RSin water,and dilute quantitatively,and stepwise if necessary,with water to obtain a solution having a known concentration of about 0.1mg per mL.

Assay preparation— Transfer about 20mg of Gemcitabine Hydrochloride,accurately weighed,to a 200-mLvolumetric flask,dissolve in and dilute with water to volume,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 275-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L7.The flow rate is about 1.2mLper minute.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the resolution,R,between the gemcitabine a-anomer and gemcitabine is not less than 8.0;and the tailing factor determined from gemcitabine is not more than 1.5.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 20µL)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 C9H11F2N3O4·HCl in the portion of Gemcitabine Hydrochloride taken by the formula: in which Cis the concentration,in mg per mL,of USP Gemcitabine Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.