A:Infrared Absorption 197K.

B:Thin-Layer Chromatographic Identification Test 201—

Test solution: 10 mg per mL, in water.

Mobile phase, Standard preparation, Test solution, and Chromatographic system— Prepare as directed in the Assay.

Procedure— Inject about 10 µL of the Test solution into the chromatograph, record the chromatogram, and measure the responses of all the peaks, except that of the solvent peak. Calculate the percentage of each peak, other than that of the solvent peak and the main ribavirin peak, by the formula: in which ri is the response of the individual peak, and rt is the sum of the responses of all the peaks in the chromatogram: not more than 0.25% of any individual peak is found, and the sum of all such peaks does not exceed 1.0%.

(Official January 1, 2007)

Mobile phase— Adjust water with sulfuric acid to a pH of 2.5 ± 0.1. Filter through a suitable filter of 0.5-µm or finer porosity, and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard preparation— Dissolve an accurately weighed quantity of USP Ribavirin RS quantitatively in Mobile phase to obtain a solution having a known concentration of about 0.025 mg per mL.

Test solution— Transfer about 50 mg of Ribavirin, accurately weighed, to a 100-mL volumetric flask, add about 50 mL of Mobile phase, swirl to dissolve, dilute with Mobile phase to volume, and mix.

Assay preparation— Transfer 5.0 mL of the Test solution to a 100-mL volumetric flask, dilute with Mobile phase to volume, and mix.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 207-nm detector and a 7.8-mm × 10-cm column that contains packing L17 and is operated at 65 ± 0.5. The flow rate is about 1 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the tailing factor for the ribavirin peak is not less than 0.7 and not more than 1.5, and the relative standard deviation for replicate injections is not more than 0.5%.

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 peak area responses for the major peaks. Calculate the quantity, in mg, of C8H12N4O5 in the portion of Ribavirin taken by the formula: in which C is the concentration, in mg per mL, of USP Ribavirin RS in the Standard preparation, and rU and rS are the ribavirin peak area responses obtained from the Assay preparation and the Standard preparation, respectively.