A: Infrared Absorption 197K.

B: Ultraviolet Absorption 1 197U—

C: Ultraviolet Absorption 2 197U—

Standard copper solution— Dissolve 1000 mg of copper wire in 6 mL of nitric acid in a 1 L volumetric flask. Add 8 mL of hydrochloric acid, dilute with water to volume, and mix. Dilute this solution quantitatively and stepwise with water to obtain a Standard copper solution having a known concentration of 0.6 µg per mL.

Test solution— Transfer 2 g of Meclofenamate Sodium, accurately weighed, to a 100-mL volumetric flask, and add 1 drop of ammonium hydroxide. Dissolve in water, dilute with water to volume, and mix.

Procedure— Concomitantly determine the absorbances of the Standard copper solution and the Test solution at the copper emission line at about 325 nm, with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering 851) equipped with a copper hollow-cathode lamp, using water as the blank. Adjust the operating conditions to obtain about 70% full-scale detector response with the Standard copper solution. The detector response obtained with the Test solution is not greater than that obtained with the Standard copper solution (0.003%).

Standard solutions— Dissolve an accurately weighed quantity of USP Meclofenamate Sodium RS in methanol to obtain a solution containing 20 mg per mL (Standard solution A). Dilute 1.0 mL of Standard solution A with sufficient methanol to obtain 200 mL of solution (Standard solution B).

Test solution— Dissolve 200 mg of Meclofenamate Sodium in 10.0 mL of methanol.

Procedure— Apply 10-µL portions of Standard solution A, Standard solution B, and the Test solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of methylene chloride, methyl ethyl ketone, and glacial acetic acid (50:48:2) until the solvent front has moved about eight-tenths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate. Examine the plate under short-wavelength UV light: the chromatograms show a principal spot at about the same RF value, and any secondary spot, if present in the chromatogram from the Test solution is not more intense than the principal spot obtained from Standard solution B (0.5%).