Effervescent Soluble Aspirin Tablets

General Notices

Effervescent Aspirin Tablets

Action and use

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

Definition

Effervescent Soluble Aspirin Tablets contain Aspirin in a suitable soluble, effervescent basis.

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

A. Dissolve with vigorous effervescence on the addition of warm water to produce a clear solution.
B. Dissolve a quantity of the powdered tablets containing 50 mg of Aspirin in 10 mL of warm water, boil and add 0.5 mL of iron(iii) chloride solution R1. A violet-red colour is produced.

TESTS

Disintegration

Comply with the requirement for Effervescent Tablets stated under Tablets.

Salicylic acid

To a quantity of the powdered tablets containing 0.50 g of Aspirin add 50 mL of dichloromethane, 2 mL of 2.5m sulfuric acid and shake vigorously for 2 minutes. Filter the dichloromethane extract through a dry filter paper containing 1 g of anhydrous sodium sulfate and evaporate 5 mL of the filtrate to dryness at room temperature using a rotary evaporator. Dissolve the residue in 2 mL of ethanol (96%), transfer to a Nessler cylinder with a further 1 mL of ethanol (96%), dilute to 50 mL with water at a temperature not exceeding 10°, add 1 mL of freshly prepared ammonium iron(iii) sulfate solution R1, mix and allow to stand for 1 minute. Any violet colour produced is not more intense than that obtained by adding 1 mL of freshly prepared ammonium iron(iii) sulfate solution R1 to a mixture of 3 mL of a freshly prepared 0.050% w/v solution of salicylic acid in ethanol (96%) and sufficient water to produce 50 mL contained in a second Nessler cylinder (3.0%).

Assay

Weigh and powder 20 tablets. Dissolve a quantity of the powder containing 0.3 g of Aspirin in 10 mL of 1M sulfuric acid and boil under a reflux condenser for 1 hour. Cool, transfer to a separating funnel, rinsing the flask and condenser with small quantities of water and extract the liberated salicylic acid with four 20-mL quantities of ether. Wash the combined ether extracts with two 5-mL quantities of water, evaporate the ether in a current of air at a temperature not exceeding 30°, dissolve the residue in 20 mL of 0.5M sodium hydroxide VS and dilute to 200 mL with water. Transfer 50 mL to a stoppered flask, add 50 mL of 0.05M bromine VS and 5 mL of hydrochloric acid, protect the solution from light, shake repeatedly during 15 minutes and allow to stand for 15 minutes. Add 20-mL of dilute potassium iodide solution shake thoroughly and titrate with 0.1M sodium thiosulfate VS, using starch mucilage, added towards the end point, as indicator. Each mL of 0.05M bromine VS is equivalent to 3.003 mg of C9H8O4.

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).

When Effervescent Soluble Aspirin Tablets are prescribed or demanded, no strength being stated, tablets containing 300 mg shall be dispensed or supplied.

When soluble aspirin tablets are prescribed, Dispersible Aspirin Tablets shall be dispensed.