Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Treatment of hyperammonaemia due to urea cycle disorders; treatment of non-ketotic hyperglycinaemia.
DEFINITION
Sodium Benzoate Oral Solution is a solution of Sodium Benzoate in a suitable vehicle.
The oral solution complies with the requirements stated under Oral Liquids and with the following requirements. Where appropriate, the oral solution also complies with the requirements stated under Unlicensed Medicines.
Content of sodium, Na
95.0 to 105.0% of the stated amount.
Content of sodium benzoate, C7H5NaO2
95.0 to 105.0% of the stated amount.
IDENTIFICATION
A. Yields reaction A characteristic of benzoates, Appendix VI.
B. Complies with the Assay for sodium.
TESTS
Acidity or alkalinity
pH, 7.0 to 7.5, Appendix V L.
ASSAY
For Na
Prepare a suitable dilution in water and determine by atomic emission spectrophotometry, Appendix II D, measuring at 589 nm and using sodium standard solution (100 ppm Na), suitably diluted with water, for the standard solutions.
For sodium benzoate
Dilute a weighed quantity of the oral solution containing 0.250 g of Sodium Benzoate to 20 mL with anhydrous acetic acid. Titrate with 0.1M perchloric acid using 0.05 mL of 1-naphtholbenzein solution as indicator, until a green colour is obtained.
Determine the weight per mL of the oral solution, Appendix V G, and calculate the content of C7H5NaO2, weight in volume. Each mL of 0.1M perchloric acid is equivalent to 14.41 mg of C7H5NaO2.
