Edition: BP 2025 (Ph. Eur. 11.6 update)
DEFINITION
Sodium Aurothiomalate Injection is a sterile solution of Sodium Aurothiomalate in Water for Injections.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of gold, Au
42.3 to 48.3% of the stated amount of Sodium Aurothiomalate.
CHARACTERISTICS
A pale yellow solution.
IDENTIFICATION
A. To a volume containing 20 mg of Sodium Aurothiomalate add 2 mL of hydrogen peroxide solution (100 vol) and 1 mL of 5M sodium hydroxide and boil for 30 seconds. A colloidal precipitate of gold is produced which appears bluish green by transmitted light.
B. To a volume containing 10 mg of Sodium Aurothiomalate add 0.1 mL of potassium cyanide solution and 0.1 mL of a 1.0% w/v solution of sodium nitroprusside. A deep magenta colour is produced.
Colour of solution
Dilute, if necessary, with water to give a solution containing 1.0% w/v of Sodium Aurothiomalate. The colour of the solution is not more intense than that of a 0.020% w/v solution of potassium hexacyanoferrate(III).
ASSAY
To a volume containing 0.1 g of Sodium Aurothiomalate, add 0.4 g of potassium bromide and 5 mL of nitric acid. Slowly evaporate the solution to dryness and continue heating until fumes cease to be evolved. Allow to cool, add 50 mL of water, warm, filter, wash the filter with hot water, dry and ignite the residue of gold, Au, for 3 hours at a temperature not lower than 600°.
STORAGE
Sodium Aurothiomalate Injection should be protected from light.
