- British Pharmacopoeia Volume III
- Formulated Preparations: Specific Monographs
Gastro-resistant Aspirin Tablets |
Salicylate; non-selective cyclo-oxygenase inhibitor; antipyretic; analgesic; anti-inflammatory.
Gastro-resistant Aspirin Tablets contain Aspirin. They are made gastro-resistant by enteric-coating or by other means.
The tablets comply with the requirements stated under Tablets and with the following requirements.
95.0 to 105.0% of the stated amount.
Boil a quantity of the powdered tablets containing 0.3 g of Aspirin for 2 to 3 minutes with 10 mL of 5m sodium hydroxide, cool and add an excess of 1m sulfuric acid; a crystalline precipitate is produced. To a solution of the precipitate in water add iron(iii) chloride solution R1; a deep violet colour is produced.
Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.
First stage
(a) Use Apparatus 1, rotating the basket at 100 revolutions per minute.
(b) Use 1000 mL of 0.1m hydrochloric acid, at a temperature of 37°, as the medium.
(1) After 2 hours, withdraw a sample of the medium, filter and measure the absorbance of the filtrate, Appendix II B, at 276 nm using 0.1m hydrochloric acid in the reference cell.
(2) Measure the absorbance of a suitable solution of aspirin BPCRS in 0.1m hydrochloric acid.
Calculate the total content of aspirin, C9H8O4, in the medium using the declared content of C9H8O4 in aspirin BPCRS. The amount of aspirin released is not more than 5% of the stated amount.
Final stage
(a) Use Apparatus 1, rotating the basket at 100 revolutions per minute.
(b) Replace the 0.1m hydrochloric acid in the vessel with 900 mL of mixed phosphate buffer pH 6.8, previously held at 36.5° to 37.5°.
(1) After 45 minutes, withdraw a sample of the medium and filter. Immediately measure the absorbance of the filtrate, Appendix II B, diluted with the dissolution medium, if necessary, at 265 nm using dissolution medium in the reference cell.
(2) Measure the absorbance of a suitable solution of aspirin BPCRS in the dissolution medium.
Calculate the total content of aspirin, C9H8O4, in the medium using the declared content of C9H8O4 in aspirin BPCRS.
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Add 60 mL of acetonitrile and 1 mL of formic acid to a quantity of powdered tablets containing 0.3 g of Aspirin, shake for 15 minutes and add sufficient acetonitrile to produce 100 mL, mix and filter.
(2) 0.009% w/v of salicylic acid in a mixture of 99 volumes of acetonitrile and 1 volume of formic acid.
(3) 0.3% w/v of aspirin BPCRS and 0.009% w/v of salicylic acid in a mixture of 99 volumes of acetonitrile and 1 volume of formic acid.
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Luna C18 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 280 nm.
(f) Inject 20 µL of each solution.
1 volume of acetonitrile and 3 volumes of 0.05m sodium dihydrogen orthophosphate adjusted to pH 2.0 with orthophosphoric acid.
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the two principal peaks is at least 3.0.
In the chromatogram obtained with solution (1):
the area of any peak corresponding to salicylic acid is not greater than the area of the peak in the chromatogram obtained with solution (2) (3%).
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Add 60 mL of acetonitrile and 1 mL of formic acid to a quantity of the powdered tablets containing 0.3 g of Aspirin, shake for 15 minutes and add sufficient acetonitrile to produce 100 mL, mix and filter. Dilute 1 volume to 4 volumes with a mixture of 99 volumes of acetonitrile and 1 volume of formic acid.
(2) 0.075% w/v of aspirin BPCRS in a mixture of 99 volumes of acetonitrile and 1 volume of formic acid.
(3) 0.075% w/v of aspirin BPCRS and 0.0015% w/v of salicylic acid in a mixture of 99 volumes of acetonitrile and 1 volume of formic acid.
The chromatographic conditions described under Salicylic acid may be used.
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the two principal peaks is at least 3.0.
determination of content
Calculate the content C9H8O4 in the tablets using the declared content of C9H8O4 in aspirin BPCRS.
Gastro-resistant Aspirin Tablets should be protected from moisture.
The label states (1) 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); (2) that the tablets should be swallowed whole and not chewed.