» Oxazepam Capsules contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C15H11ClN2O2.
Packaging and storage Preserve in well-closed containers.
Identification The solution prepared for measurement of absorbance in the Assay exhibits a maximum at 229 ± 2 nm.
Medium: 0.1 N hydrochloric acid; 1000 mL.
Apparatus 2: 75 rpm.
Time: 60 minutes.
Chromatographic system (see Chromatography 621) The liquid chromatograph is fitted with a 232-nm detector and a 4-mm × 15-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 2 mL per minute. Chromatograph the Standard solution, and record the peak response as directed for Procedure: the tailing factor for the oxazepam peak is not more than 1.5, and the relative standard deviation observed following replicate injections is not more than 3.0%. Make adjustments if necessary (see System Suitability under Chromatography 621).
Procedure Inject an accurately measured volume (about 20 µL) of a filtered portion of the solution under test into the chromatograph, record the chromatogram, and measure the response for the major peak. Calculate the quantity of C15H11ClN2O2 dissolved in comparison with a Standard solution having a known concentration of USP Oxazepam RS in 0.1 N hydrochloric acid [notea volume of methanol not to exceed 10% of the final total volume may be used to dissolve the Oxazepam reference standard] and similarly chromatographed.
Tolerances Not less than 75% (Q) of the labeled amount of C15H11ClN2O2 is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay Remove, as completely as possible, the contents of not less than 20 Capsules, and weigh. Transfer an accurately weighed portion of the mixed powder, equivalent to about 50 mg of oxazepam, to a medium-porosity, sintered-glass funnel that is fitted into a small suction flask. Add 25 mL of alcohol, mix with the aid of a stirring rod, and after about 5 minutes apply gentle suction to remove the extract. Repeat the extraction with four additional 25-mL portions of alcohol, transfer the extracts to a 250-mL volumetric flask, dilute with alcohol to volume, and mix. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, dilute with alcohol to volume, and mix. Concomitantly determine the absorbances of this solution and of a Standard solution of USP Oxazepam RS in the same medium having a known concentration of about 4 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 229 nm, with a suitable spectrophotometer, using alcohol as the blank. Calculate the quantity, in mg, of C15H11ClN2O2 in the portion of Capsules taken by the formula:
12.5C(AU / AS)in which C is the concentration, in µg per mL, of USP Oxazepam RS in the Standard solution, and AU and AS are the absorbances of the solution from the Capsules and the Standard solution, respectively.
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USP32NF27 Page 3154
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.