Dissolution á711ñ—
Medium:
0.1Nhydrochloric acid;1000mL.
Apparatus 2:
50rpm.
Time:
60minutes.
Chromatographic system—
The liquid chromatograph is fitted with a 232-nm detector and a 4-mm ×30-cm column that contains packing L7.The mobile phase is a degassed mixture of methanol,water,and glacial acetic acid (60:40:1),and the flow rate is about 2mLper minute.In a suitable system,the relative standard deviation observed following replicate injections is not more than 3.0%.
Procedure—
Inject an accurately measured volume (about 10µL)of a filtered portion of the solution under test into the chromatograph by means of a microsyringe or a sampling valve,record the chromatogram,and measure the response for the major peak.Calculate the quantity of C
15H
11ClN
2O
2dissolved in comparison with a similarly chromatographed Standard solution having a known concentration of
USP Oxazepam RSin 0.1Nhydrochloric acid.
[NOTE—Avolume of alcohol not exceeding 10%of the final total volume of the Standard solution may be used to dissolve the Reference Standard.
]
Tolerances—
Not less than 80%(Q)of the labeled amount of C15H11ClN2O2is dissolved in 60minutes.
Assay—
Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 50mg of oxazepam,to a medium-porosity,sintered-glass funnel that is fitted into a small suction flask,and proceed as directed in the
Assayunder
Oxazepam Capsules,beginning with “Add 25mLof alcohol.”Calculate the quantity,in mg,of C
15H
11ClN
2O
2in the portion of Tablets taken by the formula:
12.5C(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Oxazepam RSin the Standard solution,and
AUand
ASare the absorbances of the solution from the Tablets and the Standard solution,respectively.