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Assay—
Mobile phase— Use degassed and filtered water.
Standard preparation— Dissolve an accurately weighed quantity of USP Fluorouracil RS in water, and dilute quantitatively, and stepwise if necessary, with water to obtain a solution having a known concentration of about 10 µg per mL.
Assay preparation— Transfer an accurately weighed quantity of about 20 mg of Fluorouracil to a 200-mL volumetric flask, dissolve in and dilute with water to volume, and mix. Quantitatively dilute a known volume of this solution with water to obtain a solution having a concentration of about 10 µg per mL.
Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column containing packing L1. The flow rate is about 1 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 2500 theoretical plates, and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject equal volumes (about 10 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 C4H3FN2O2 in the portion of Fluorouracil taken by the formula:
2C(rU / rS)
in which C is the concentration, in µg per mL, of USP Fluorouracil RS in the Standard preparation; and rU and rS are the fluorouracil peak responses obtained from the Assay preparation and the Standard preparation, respectively. |
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