Aspirin Tablets

General Notices

Acetylsalicylic Acid Tablets

Action and use

Salicylate; non-selective cyclo-oxygenase inhibitor; antipyretic; analgesic; anti-inflammatory.

Definition

Aspirin Tablets contain Aspirin.

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

Content of aspirin, C9H8O4

95.0 to 105.0% of the stated amount.

Identification

Shake a quantity of the powdered tablets containing 0.5 g of Aspirin with 20 mL of absolute ethanol, filter (Whatman GF/C is suitable), evaporate the filtrate and dry the residue at 60° for 1 hour. The infrared absorption spectrum of the residue, is concordant with the reference spectrum of aspirin (RS 483).

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 1, rotating the basket at 50 revolutions per minute.
(b) Use 500 mL of a pH 4.5 buffer prepared by mixing 29.9 g of sodium acetate and 16.6 mL of glacial acetic acid with sufficient water to produce 10 litres at a temperature of 37°, as the medium.
procedure
(1) After 45 minutes withdraw a sample of the medium and measure the absorbance of the filtered sample, suitably diluted with the dissolution medium if necessary, at the maximum at 265 nm, Appendix II B using dissolution medium in the reference cell.
(2) Measure the absorbance of a suitable solution of aspirin BPCRS using dissolution medium in the reference cell.
determination of content

Calculate the total content of aspirin, C9H8O4, in the medium using the declared content of C9H8O4 in aspirin BPCRS.

Related substances

Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared immediately before use.

(1) Mix with the aid of ultrasound for 15 minutes a quantity of the powdered tablets containing 0.10 g of Aspirin with 40 mL of acetonitrile, allow to cool, dilute to 100 mL with water and filter through a 0.45-µm PTFE filter.
(2) Dilute 1 volume of solution (1) to 50 volumes and further dilute 1 volume of the resulting solution to 10 volumes with the mobile phase.
(3) 0.003% w/v of salicylic acid (impurity C) in the mobile phase.
(4) 0.1% w/v of aspirin impurity standard BPCRS in the mobile phase.
chromatographic conditions
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Kromasil C18 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1.0 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 237 nm.
(f) Inject 20 µL of each solution.
(g) Allow the chromatography to proceed for 1.2 times the retention time of impurity F.
mobile phase

2 volumes of orthophosphoric acid, 400 volumes of acetonitrile and 600 volumes of water.

When the chromatograms are recorded under the prescribed conditions, the retention times relative to aspirin (retention time about 5 minutes) are: impurity A, about 0.6; impurity B, about 0.7, impurity C, about 1.4 and impurity F, about 8.0.

system suitability

The test is not valid unless, in the chromatogram obtained with solution (4) the resolution between the peaks due to aspirin and impurity C is at least 6.

limits

In the chromatogram obtained with solution (1):

the area of any peak corresponding to impurity C is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (3%);

the area of any other secondary peak is not greater than half of the area of the principal peak in the chromatogram obtained with solution (2) (0.1%);

the sum of the areas of any other secondary peaks is not greater than 5 times the area of the principal peak in the chromatogram obtained with solution (2) (1.0%).

Disregard any peak with an area less than 0.25 times the area of the principal peak in the chromatogram obtained with solution (2) (0.05%).

Assay

Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared immediately before use.

(1) Mix with the aid of ultrasound for 15 minutes a quantity of the powdered tablets containing 60 mg of Aspirin with 40 mL of acetonitrile, allow to cool, dilute to 100 mL with water and filter through a 0.45-µm PTFE filter.
(2) 0.06% w/v of aspirin BPCRS in the mobile phase.
(3) 0.1% w/v of aspirin impurity standard BPCRS in the mobile phase.
chromatographic conditions

The chromatographic procedure described under Related substances may be used.

system suitability

The test is not valid unless, in the chromatogram obtained with solution (3) the resolution between the peaks due to aspirin and impurity C is at least 6.0.

determination of content

Calculate the content of C9H8O4 in the tablets from the chromatograms obtained using the declared content of C9H8O4 in aspirin BPCRS.

Labelling

The label states that the tablets contain Aspirin, unless this word appears in the name of the tablets. This requirement does not apply in countries where exclusive proprietary rights in the name Aspirin are claimed.

IMPURITIES

The impurities limited by the requirements of this monograph include those listed under Aspirin.