Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Cholinesterase inhibitor.
DEFINITION
Edrophonium Injection is a sterile solution of Edrophonium Chloride in Water for Injections.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of edrophonium chloride, C10H16ClNO
95.0 to 105.0% of the stated amount.
IDENTIFICATION
A. Dilute a sufficient volume of the injection with 0.1M sodium hydroxide to give a solution containing 0.001% w/v of Edrophonium Chloride. The light absorption of the resulting solution, Appendix II B, in the range 220 to 350 nm exhibits two maxima, at 240 nm and 294 nm. The absorbances at the maxima are about 1.1 and about 0.34 respectively.
B. To a volume containing 20 mg of Edrophonium Chloride add 0.05 mL of iron(III) chloride solution R1. A reddish violet colour is produced.
C. Yields reaction A characteristic of chlorides, Appendix VI.
TESTS
Acidity
pH, 5.0 to 6.0, Appendix V L.
Dimethylaminophenol
To a volume containing 50 mg of Edrophonium Chloride add 10 mL of phosphate buffer pH 8.0 and extract with two 20 mL quantities of chloroform. Wash the extracts successively with two 10 mL quantities of water, extract with 10 mL of 0.1M sodium hydroxide and discard the chloroform. The absorbance of the resulting solution at 293 nm is not more than 0.125, Appendix II B.
ASSAY
To a volume containing 50 mg of Edrophonium Chloride add sufficient water to produce 100 mL. Dilute 10 mL of this solution to 100 mL with water and measure the absorbance of the resulting solution at the maximum at 273 nm, Appendix II B. Calculate the content of C10H16ClNO taking 110 as the value of A (1%, 1 cm) at the maximum at 273 nm.
STORAGE
Edrophonium Injection should be protected from light.
