A: Infrared Absorption 197K.

B: It meets the requirements of the tests for Chloride 191.

Test solution: 10 mg per mL.

Solution A— Proceed as directed for Mobile phase in the Assay.

Solution B— Prepare filtered and degassed methanol.

Mobile phase— Use variable mixtures of Solution A and Solution B as directed under Chromatographic system. Make adjustments, if necessary (see System Suitability under Chromatography 621).

System suitability solution— Proceed as directed in the Assay.

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

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

Chromatographic system (see Chromatography 621)— 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 0.5 for gemcitabine -anomer and 1.0 for gemcitabine; the resolution, R, between gemcitabine -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 0.1 for cytosine and 1.0 for gemcitabine; the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject a volume (about 20 µL) of the Standard solution and Test solution into 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 Cc is the concentration of USP Cytosine RS in the Standard solution, in µg per mL; W is the weight, in mg, of Gemcitabine taken; rt is the peak response for cytosine in the Test solution; and rs is the response for cytosine in the Standard 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 Cs is the concentration of USP Gemcitabine Hydrochloride RS in the Standard solution, in µg per mL; W is the weight, in mg, of Gemcitabine taken; ri is the peak response for each impurity in the Test solution; and rs is the response due to gemcitabine in the Standard solution: not more than 0.1% of gemcitabine -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 13.8 g of monobasic sodium phosphate and 2.5 mL of phosphoric acid in 1000 mL of water. [note—The pH of this solution is between 2.4 and 2.6.]

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

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

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

Chromatographic system (see Chromatography 621)— 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 1.2 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the resolution, R, between the gemcitabine -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 20 µL) of the Standard preparation and the Assay preparation into 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 C is the concentration, in mg per mL, of USP Gemcitabine Hydrochloride RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.