Fenoprofen Tablets

General Notices

Action and use

Cyclo-oxygenase inhibitor; analgesic; anti-inflammatory.

Definition

Fenoprofen Tablets contain Fenoprofen Calcium. They are coated.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of fenoprofen, C₁₅H₁₄O₃

95.0 to 105.0% of the stated amount.

Identification

A. The light absorption, Appendix II B, in the range 230 to 350 nm of the final solution obtained in the Assay exhibits two maxima, at 272 nm and 278 nm, and a shoulder at 266 nm.

B. Suspend a quantity of the powdered tablets containing the equivalent of 0.3 g of fenoprofen in 10 mL of 0.1m hydrochloric acid. Extract with 20 mL of chloroform, filter the extract through anhydrous sodium sulfate and evaporate the filtrate to dryness. The infrared absorption spectrum of a thin film of the residue, Appendix II A, is concordant with the reference spectrum of fenoprofen (RS 141).

C. Ignite a quantity of the powdered tablets. The residue yields the reactions characteristic of calcium salts, Appendix VI.

Related substances

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) To a quantity of the powdered tablets containing the equivalent of 0.5 g of fenoprofen add 80 mL of the mobile phase, mix with the aid of ultrasound, allow to cool, add sufficient mobile phase to produce 100 mL and filter.

(2) Dilute 1 volume of solution (1) to 200 volumes with the mobile phase.

(3) 0.04% w/v of fenoprofen calcium and 0.0015% w/v of 4,4′-dimethoxybenzophenone in the mobile phase.

(4) Dilute 1 volume of solution (2) to 5 volumes with the mobile phase.

chromatographic conditions

(a) Use a stainless steel column (25 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (7 to 8 µm) (Zorbax ODS is suitable).

(b) Use isocratic elution and the mobile phase described below.

(d) Use an ambient column temperature.

(e) Use a detection wavelength of 270 nm.

(f) Inject 20 µL of each solution.

(g) For solution (1) allow the chromatography to proceed for 3 times the retention time of the peak due to fenoprofen.

mobile phase

2 volumes of glacial acetic acid, 7 volumes of tetrahydrofuran, 30 volumes of acetonitrile and 61 volumes of water.

system suitability

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks corresponding to fenoprofen calcium and 4′,4′-dimethoxybenzophenone is at least 3.0.

limits

In the chromatogram obtained with solution (1):

the area of any secondary peak is not greater than twice the area of the peak in the chromatogram obtained with solution (2) (1.0%);

not more than one such peak has an area greater than the area of the peak in the chromatogram obtained with solution (2) (0.5%);

the sum of the areas of all such peaks is not greater than four times the area of the peak in the chromatogram obtained with solution (2) (2%).

Disregard any peak with an area less than that of the principal peak in the chromatogram obtained with solution (4) (0.1%).

Assay

Weigh and powder 20 tablets. To a quantity of the powder containing the equivalent of 0.2 g of fenoprofen add 5 mL of glacial acetic acid and shake for 1 minute. Add 100 mL of methanol, shake for 5 minutes, dilute to 200 mL with methanol and filter. Dilute 10 mL of the filtrate to 200 mL with methanol and measure the absorbance of the resulting solution at the maximum at 272 nm, Appendix II B. Calculate the content of C₁₅H₁₄O₃ taking 80.7 as the value of A (1%, 1 cm) at the maximum at 272 nm.

Labelling

The quantity of active ingredient is stated in terms of the equivalent amount of fenoprofen.