Oxaprozin Tablets

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

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

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1 DEFINITION

Oxaprozin Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of oxaprozin (C₁₈H₁₅NO₃).

[NOTE-Because of light sensitivity, protect all oxaprozin samples and standard solutions from light.]

2 IDENTIFICATION

A. THIN-LAYER CHROMATOGRAPHIC IDENTIFICATION TEST (201)

Sample solution: 2 mg/mL of oxaprozin in acetone

Developing solvent system: Ethyl acetate and glacial acetic acid (99:1)

Acceptance criteria: Meet the requirements

B. 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

Solution A: 0.1% Phosphoric acid. Add phosphoric acid, dropwise, to water to obtain a pH of 2.00 ± 0.10.

Mobile phase: Acetonitrile and Solution A (45:55)

Standard solution: Dissolve an accurately weighed quantity of USP Oxaprozin RS in acetonitrile to obtain a solution having a concentration of about 12 µg/mL of oxaprozin.

Sample stock solution: Nominally 0.6 mg/mL of oxaprozin prepared as follows. Transfer a suitable amount of oxaprozin from NLT 20 powdered Tablets to an appropriate volumetric flask. Add water to 10% of the final volume, and sonicate for 10 min. Add 40% of the final volume of acetonitrile, and sonicate for 30 min. Shake by mechanical means for an additional 30 min. Add 30% of the final volume of acetonitrile, and sonicate for 10 min. Dilute with acetonitrile to volume. Pass through a suitable filter. Use the filtrate.

Sample solution: Nominally equivalent to 12 µg/mL of oxaprozin from the Sample stock solution in acetonitrile

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 285 nm

Column: 4.6-mm x 15-cm; 5-µm packing L7

Flow rate: 1.0 mL/min

Injection volume: 20 µL

3.3 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of oxaprozin (C₁₈H₁₅NO₃) in the portion of Tablets 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 Oxaprozin RS in the Standard solution (mg/mL)

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

Acceptance criteria: 95.0%-105.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: 0.05 M monobasic potassium phosphate buffer, pH 7.4; 1000 mL

Apparatus 2: 75 rpm

Time: 45 min

Detector: UV 286 nm (maximum absorbance)

Standard solution: A known concentration of USP Oxaprozin RS in Medium. [NOTE-A quantity of methanol, not exceeding 5% of the final volume, can be added to help solubilize the USP Reference Standard.]

Sample solution: Filter portions of the solution under test, suitably diluted with Medium, if necessary.

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of oxaprozin (C₁₈H₁₅NO₃) dissolved by using UV absorption from the Sample solution in comparison with the Standard solution.

Tolerances: NLT 75% (Q) of the labeled amount of oxaprozin (C₁₈H₁₅NO₃) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

Solution A and Mobile phase: Proceed as directed in the Assay.

Standard solution: 0.001 mg/mL of USP Oxaprozin RS in acetonitrile

Sample solution: Nominally 1 mg/mL of oxaprozin prepared as follows. Transfer a suitable amount of oxaprozin from NLT 20 powdered Tablets to an appropriate volumetric flask. Add water to 10% of the final volume, and sonicate for 10 min. Add 40% of the final volume of acetonitrile, and sonicate for 30 min. Shake by mechanical means for an additional 30 min. Add 30% of the final volume of acetonitrile, and sonicate for 10 min. Dilute with acetonitrile to volume. Pass through a suitable filter. Use the filtrate.

Chromatographic system: Proceed as directed in the Assay except use a column temperature of 20°.

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 5.0%

Analysis

Samples: Standard solution and Sample solution

nd each in Calculate the percentages of benzoin, benzil, and each individual unspecified degradation product in the portion of Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) x (1/F) x 100

r_U = peak response of benzoin, benzil, or each individual unspecified degradation product from the Sample solution

r_S = peak response of oxaprozin from the Standard solution

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

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

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1.

Table 1

^a 2-Hydroxy-1,2-diphenylethan-1-one.

6 SPECIFIC TESTS

WATER DETERMINATION, Method la(921): NMT 3.5%

7 ADDITIONAL REQUIREMENTS

7.1 PACKAGING AND STORAGE

Preserve in tight, light-resistant containers, and store at controlled room temperature.

7.2 USP REFERENCE STANDARDS (11)

USP Oxaprozin RS