Bacterial endotoxins 85
Where the label states that Vidarabine is sterile or must be subjected to further processing during the processing of injectable dosage forms, it contains not more than 0.5 USP Endotoxin Unit per mg of vidarabine. Where it is intended for use in preparing ophthalmic dosage forms, it is exempt from the requirements.
Sterility 71
Where the label states that Vidarabine is sterile, it meets the requirements when tested as directed for
Direct Inoculation of the Culture Medium under
Test for Sterility of the Product to be Examined, except to transfer 2 g of solid specimen to each test medium.
Assay
Mobile phase
Dissolve 2.2 g of docusate sodium in 10 mL of glacial acetic acid and 500 mL of methanol in a 1000-mL volumetric flask. Dilute with water to volume, and mix. Pass this solution through a membrane filter having a 1-µm or finer porosity.
Standard preparation
Dissolve about 24 mg of
USP Vidarabine RS, accurately weighed, in 150 mL of water in a 200-mL volumetric flask by heating to 100
for 10 minutes. Cool, dilute with water to volume, and mix.
Assay preparation
Using Vidarabine, prepare as directed for Standard preparation.
Chromatographic system
(see
Chromatography 621)The chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains packing L1. Chromatograph three replicate injections of the
Standard preparation, and record the peak responses as directed for
Procedure: the relative standard deviation is not more than 3.0%.
Procedure
Introduce equal volumes (approximately 10 µL) of the
Assay preparation and the
Standard preparation into the instrument, operated at room temperature, by means of a suitable microsyringe or sampling valve. Adjust the operating conditions so that satisfactory chromatography and peak responses are obtained. Use a detector sensitivity setting that gives a peak height for vidarabine that is at least 50% of scale. Measure peak responses at the same retention times obtained with the
Assay preparation and the
Standard preparation. Calculate the potency, in µg of C
10H
13 N
5O
4 per mg, of the Vidarabine taken by the formula:
F(rU / rS)(WS / WU),
in which
F is the potency of
USP Vidarabine RS, in µg of vidarabine per mg;
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively; and
WU and
WS are the amounts, in mg, of
USP Vidarabine RS and Vidarabine taken, respectively.