Naproxen Tablets

General Notices

Action and use

Cyclo-oxygenase inhibitor; analgesic; anti-inflammatory.

Definition

Naproxen Tablets contain Naproxen.

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

Content of naproxen, C14H14O3

95.0 to 105.0% of the stated amount.

Identification

A. Extract a quantity of the powdered tablets containing 20 mg of Naproxen with sufficient methanol to produce 100 mL and filter. Reserve 10 mL of the filtrate for test B, evaporate the remainder and dry the residue at 105°. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of naproxen (RS 244).
B. Dilute the 10 mL quantity of the filtrate reserved in test A to 100 mL with methanol. The light absorption of the resulting solution, Appendix II B, in the range 230 to 350 nm exhibits maxima at 262, 271, 316 and 331 nm.

Tests

Dissolution

Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.

test conditions
(a) Use Apparatus 2, rotating the paddle at 50 revolutions per minute.
(b) Use 900 mL of phosphate buffer, prepared by dissolving 2.62 g of sodium dihydrogen orthophosphate monohydrate and 11.50 g of anhydrous disodium hydrogen orthophosphate in sufficient water to produce 1 L, and adjusting the pH to 7.4 with either 0.1m sodium hydroxide or 0.1m hydrochloric acid if necessary, at a temperature of 37°, as the medium.
procedure
(1) After 45 minutes withdraw a 10 mL sample of the medium and measure the absorbance of the filtered sample, suitably diluted with the dissolution medium if necessary, at the maximum at 332 nm, Appendix II B using dissolution medium in the reference cell.
(2) Measure the absorbance of a suitable solution of naproxen BPCRS in dissolution medium in the reference cell.
determination of content

Calculate the total content of naproxen, C14H14O3, in the medium using the declared content of C14H14O3 in naproxen BPCRS.

Related substances

Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.

(1) Shake a quantity of the powdered tablets containing 0.5 g of Naproxen with 10 mL of methanol for 15 minutes, centrifuge and use the supernatant liquid.
(2) Dilute 1 volume of solution (1) to 200 volumes with methanol.
chromatographic conditions
(a) Use a silica gel coated plate.
(b) Use the mobile phase as described below.
(c) Apply 10 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry in air and examine under ultraviolet light (254 nm).
mobile phase

3 volumes of glacial acetic acid, 9 volumes of tetrahydrofuran and 90 volumes of toluene.

limits

Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%).

Assay

Weigh and powder 20 tablets. Shake a quantity of the powder containing 50 mg of Naproxen with 70 mL of methanol for 30 minutes, add sufficient methanol to produce 100 mL and filter. Dilute 10 mL of the filtrate to 50 mL with methanol and measure the absorbance at the maximum at 331 nm, Appendix II B. Calculate the content of C14H14O3 from the absorbance obtained by repeating the operation using a 0.01% w/v solution of naproxen BPCRS in methanol and using the declared content of C14H14O3 in naproxen BPCRS.

Storage

Naproxen Tablets should be protected from light.