Indometacin Capsules

General Notices

Action and use

Cyclo-oxygenase inhibitor; analgesic; anti-inflammatory.

Definition

Indometacin Capsules contain Indometacin.

The capsules comply with the requirements stated under Capsules and with the following requirements.

Content of indometacin, C19H16ClNO4

90.0 to 110.0% of the stated amount.

Identification

A. Shake a quantity of the contents of the capsules containing 0.1 g of Indometacin with 5 mL of chloroform, filter and evaporate the filtrate to dryness. Dry the residue at 60° at a pressure not exceeding 0.7 kPa for 1 hour. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of indometacin (RS 187).
B. The light absorption, Appendix II B, in the range 300 to 350 nm of the solution obtained in the Assay exhibits a maximum only at 320 nm.
C. Mix a quantity of the contents of the capsules containing 25 mg of Indometacin with 2 mL of water and add 2 mL of 2m sodium hydroxide. A bright yellow colour is produced which fades rapidly.

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 pH 7.2, at a temperature of 37°, as the medium.
procedure
(1) 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 320 nm, Appendix II B using phosphate buffer pH 7.2 in the reference cell.
determination of content

Calculate the total content of indometacin, C19H16ClNO4, in the medium taking 196 as the value of A(1%, 1 cm) at the maximum at 320 nm.

Related substances

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

(1) Shake a quantity of the contents of the capsules containing 0.10 g of Indometacin with 5 mL of chloroform, filter and use the filtrate.
(2) Dilute 1 volume of solution (1) to 200 volumes with chloroform.
chromatographic conditions
(a) Use a suspension of silica gel HF254 in a 4.68% w/v solution of sodium dihydrogen orthophosphate to coat the plate.
(b) Use the mobile phase as described below.
(c) Apply 5 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

30 volumes of petroleum spirit (boiling range, 60° to 80°) and 70 volumes of ether.

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).

Assay

To a quantity of the mixed contents of 20 capsules containing 50 mg of Indometacin add 10 mL of water and allow to stand for 10 minutes, swirling occasionally. Add 75 mL of methanol, shake well, add sufficient methanol to produce 100 mL and filter if necessary. To 5 mL of the filtrate add sufficient of a mixture of equal volumes of methanol and phosphate buffer pH 7.2 to produce 100 mL. Measure the absorbance of the resulting solution at the maximum at 320 nm, Appendix II B. Calculate the content of C19H16ClNO4 taking 193 as the value of A(1%, 1 cm) at the maximum at 320 nm.