Naproxen
;)
2-Naphthaleneacetic acid,6-methoxy-a-methyl-,(S)-.
(+)-(S)-6-Methoxy-a-methyl-2-naphthaleneacetic acid [22204-53-1].
»Naproxen contains not less than 98.5percent and not more than 101.5percent of C14H14O3,calculated on the dried basis.
Packaging and storage—
Preserve in tight containers.
Identification—
A:
Infrared Absorption á197Kñ.
B:
Ultraviolet Absorption á197Uñ—
Solution:
25µg per mL.
Medium:
methanol.
Absorptivities at 271nm,calculated on the dried basis,do not differ by more than 3%.
Specific rotation á781Sñ:
between +63.0
and +68.5.
and +68.5.
Test solution:
10mg per mL,in chloroform.
Loss on drying á731ñ—
Dry it at 105for 3hours:it loses not more than 0.5%of its weight.
for 3hours:it loses not more than 0.5%of its weight.
Heavy metals,Method IIá231ñ:
0.002%.
Chromatographic purity—
Dissolve 100mg of Naproxen in methanol,and dilute with methanol to 5.0mLto obtain the Test solution.Dissolve a suitable quantity of USP Naproxen RSin methanol to obtain a Standard solutionhaving a known concentration of about 20mg per mL.Dilute a portion of this solution quantitatively and stepwise with methanol to obtain three Comparison solutionshaving concentrations of 20,60,and 100µg per mL(0.1%,0.3%,and 0.5%of the Standard solution),respectively.Apply separate 10-µLportions of the five solutions to the starting line of a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatogram in a solvent system consisting of a mixture of toluene,tetrahydrofuran,and glacial acetic acid (30:3:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chamber,mark the solvent front,air-dry,and view under short-wavelength UVlight:the RFvalue of the principal spot in the chromatogram of the Test solutioncorresponds to that of the Standard solution,and any other spot obtained from the Test solutiondoes not exceed,in size or intensity,the principal spot obtained from the 100-µg-per-mLComparison solution(0.5%),and the sum of the intensities of any secondary spots,similarly compared,does not exceed 2.0%.
Organic volatile impurities,Method Vá467ñ:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Dissolve about 500mg of Naproxen,accurately weighed,in a mixture of 75mLof methanol and 25mLof water that has been previously neutralized to the phenolphthalein endpoint with 0.1Nsodium hydroxide.Dissolve by gentle warming,if necessary,add phenolphthalein TS,and titrate with 0.1Nsodium hydroxide VS.Each mLof 0.1Nsodium hydroxide is equivalent to 23.03mg of C14H14O3.
Auxiliary Information—
Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist
Expert Committee:(PA2)Pharmaceutical Analysis 2
USP28–NF23Page 1335
Pharmacopeial Forum:Volume No.30(3)Page 904
Phone Number:1-301-816-8139