2-Oxazolepropanoic acid, 4,5-diphenyl-.
4,5-Diphenyl-2-oxazolepropionic acid [21256-18-8].
» Oxaprozin contains not less than 98.5 percent and not more than 101.5 percent of C18H15NO3, calculated on the dried basis.
noteBecause of light sensitivity, protect all oxaprozin samples and Standard solutions from light.
Packaging and storage Preserve in tight, light-resistant containers, and store at controlled room temperature.
A: Infrared Absorption 197K: previously dried at 105 for 2 hours.
B: Ultraviolet Absorption 197U: previously dried at 105 for 2 hours. The absorbance of the sample at 285 nm is between 0.455 and 0.495.
Solution: 10 µg per mL.
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.3% of its weight.
Residue on ignition 281: not more than 0.3%.
Arsenic, Method II 211: 1 µg per g.
Heavy metals, Method II 231: 0.001%.
Solution A: 0.1% phosphoric acid adjusted with phosphoric acid to a pH of 2.00 ± 0.1.
Solution B Use acetonitrile.
Mobile phase Use variable mixtures of Solution A and Solution B as directed for Chromatographic system. Make adjustments if necessary (see System Suitability under Chromatography 621).
Diluent A: a mixture of acetonitrile, methylene chloride, and water (48:1:1).
Diluent B: a mixture of acetonitrile and water (1:1).
Standard stock solution Dissolve an accurately weighed quantity of USP Oxaprozin RS in acetonitrile to obtain a solution having a concentration of about 200 µg per mL.
Standard solution Transfer 5.0 mL of Standard stock solution to a 200-mL volumetric flask, and dilute with Diluent A to volume.
Benzil solution: 200 µg of benzil per mL in acetonitrile.
Resolution solution Transfer 5.0 mL of Benzil solution and 5.0 mL of Standard stock solution to a 100-mL volumetric flask, and dilute with Diluent A to volume to obtain a solution having known concentrations of about 10 µg of each per mL.
Test solution A [noteTest solution A is used to monitor all known and unknown impurities, except imidazolic acid and oximide.] Transfer about 100 mg of Oxaprozin, accurately weighed, to a 100-mL volumetric flask; add 2 mL of methylene chloride, 2 mL of water, and 75 mL of acetonitrile; and sonicate after each solvent is added. Dilute with acetonitrile to volume.
Test solution B [noteTest solution B is used to monitor only imidazolic acid and oximide.] Transfer about 100 mg of Oxaprozin, accurately weighed, to a 100-mL volumetric flask; add 75 mL of Diluent B to dissolve the Oxaprozin; and dilute with Diluent B to volume.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 238-nm detector and a 4.6-mm × 15-cm column that contains 5-µm packing L7. The flow rate is 1.0 mL per minute. The chromatograph is programmed as follows.
Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times are about 1.1 for benzil and 1.0 for oxaprozin; and the resolution, R, between oxaprozin and benzil is not less than 3.0. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.0, and the relative standard deviation for replicate injections is not more than 5.0%.
Procedure Inject 20 µL of Test solution A and Test solution B into the chromatograph, record the chromatogram, and measure the areas for all the peaks. Calculate the percentage of each impurity in the portion of Oxaprozin taken by the formula:
100(Fri / rs)in which F is the relative response factor and is equal to 1.15 for the imidazolic acid peak with a relative retention time of 0.14, 1.21 for any peak with a relative retention time of 0.42, 0.91 for the oximide peak with a relative retention time of 0.73, 0.85 for any peak with a relative retention time of 0.84, 1.29 for any peak with a relative retention time of 1.08, 1.46 for any peak with a relative retention time of 1.50, and 2.09 for any peak with a relative retention time of 1.57; ri is the peak response for each impurity; and rs is the sum of the responses of all the peaks: not more than 0.1% of any individual impurity is found, and not more than 0.5% of total impurities is found. [noteThe values of F for all known impurities except imidazolic acid and oximide were found using Test solution A, and the values of F for imidazolic acid and oximide were found using Test solution B.]
Assay Dissolve about 400 mg of Oxaprozin, previously dried at 105 for 2 hours and accurately weighed, in about 100 mL of alcohol in a narrow-mouth container, and titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically (see Titrimetry 541). Each mL of 0.1 N sodium hydroxide is equivalent to 29.332 mg of oxaprozin.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 3152Pharmacopeial Forum: Volume No. 32(1) Page 130
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.