Oxazepam Capsules

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Oxazepam Capsules contain NLT 90.0% and NMT 110.0% of the labeled amount of C₁₅H₁₁ClN₂O₂.

2 IDENTIFICATION

The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Diluent: Methanol and water (9:1)

Buffer: 8.5 g/L of monobasic potassium phosphate in water. Adjust with 1 N sodium hydroxide to a pH of 6.5.

Mobile phase: Methanol and Buffer (3:2)

Standard solution: 0.1 mg/mL of USP Oxazepam RS in Diluent

Sample solution: 0.1 mg/mL of oxazepam in Diluent, from the contents of NLT 20 Capsules. [NOTE-Sonicate for 15 min and shake for 15 min. Pass through a filter of 0.45-µm pore size.]

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 232 nm

Column: 4.6-mm × 15-cm; 5-µm packing L1

Flow rate: 1 mL/min

Injection size: 20 µL

Run time: At least 1.7 times the retention time of oxazepam

3.3 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₁₅H₁₁ClN₂O₂, in the portion of Capsules taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Oxazepam RS in the Standard solution (mg/mL)

C_U = nominal concentration of oxazepam in the Sample solution (mg/mL)

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: 0.1 N hydrochloric acid; 1000 mL

Apparatus 2: 75 rpm

Time: 60 min

Standard stock solution: 0.1 mg/mL of USP Oxazepam RS in methanol

[NOTE-Prepare NMT 30 min before use.]

Standard solution: 0.01 mg/mL of USP Oxazepam RS in Medium from the Standard stock solution. [NOTE-Keep it at about 6° for the Analysis. This solution is stable for 72 h if kept refrigerated.]

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size. Keep it at about 6° for the Analysis.

Mobile phase: Methanol, water, and glacial acetic acid (60:40:1)

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 232 nm

Column: 4-mm x 15-cm; packing L7

Flow rate: 2 mL/min

Injection size: 20 µL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5 for the oxazepam peak

Relative standard deviation: NMT 3.0%

Analysis

Samples: Standard solution and Sample solution

Tolerances: NLT 75% (Q) of the labeled amount of C₁₅H₁₁ClN₂O₂, is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

PROCEDURE

Diluent, Buffer, and Mobile phase: Proceed as directed in the Assay.

Standard solution: 2 µg/mL of USP Oxazepam RS in Diluent

Sample solution: 0.2 mg/mL of oxazepam in Diluent, from the contents of NLT 20 Capsules. [NOTE-Sonicate for 15 min and shake for 15 min. Pass through a filter of 0.45-µm pore size.]

Chromatographic system: Proceed as directed in the Assay.

Run time: 3.5 times the retention time of oxazepam

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Capsules taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response of each individual impurity from the Sample solution

r_S = peak response of oxazepam from the Standard solution

C_S = concentration of USP Oxazepam RS in the Standard solution (µg/mL)

C_U = nominal concentration of oxazepam in the Sample solution (µg/mL)

Acceptance criteria

Individual impurities: See Impurity Table 1. [NOTE-Disregard peaks less than 0.05%.]

Total impurities: NMT 0.5%, not including 2-amino 5-chlorobenzophenone

Impurity Table 1

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in well-closed containers.

6.2 USP REFERENCE STANDARDS (11)

USP Oxazepam RS