Edition: BP 2025 (Ph. Eur. 11.6 update)
DEFINITION
Phenol and Glycerol Injection is a sterile solution containing 5% w/v of Phenol in Glycerol that has been previously dried at 120° for 1 hour.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of phenol, C6H6O
4.75 to 5.25% w/v.
CHARACTERISTICS
A pale straw-coloured, viscous solution.
IDENTIFICATION
A. Add bromine water to a 1% w/v solution. A white precipitate is produced, which, on the continued addition of bromine water, at first dissolves then reappears and becomes permanent.
B. To 0.5 mL add 5 mL of water and 0.05 mL of sodium nitrite solution and carefully pour on to the surface of sulfuric acid. A coloured zone, red above and green below, appears at the junction of the two layers.
C. When heated on a borax bead in a naked flame, it imparts a green colour to the flame.
ASSAY
Dissolve 2 g in sufficient water to produce 50 mL, transfer 25 mL to a 500 mL glass-stoppered flask and add 50 mL of 0.05 M bromine VS and 5 mL of hydrochloric acid, stopper, swirl occasionally during 30 minutes and allow to stand for a further 15 minutes. Add 5 mL of a 20% w/v solution of potassium iodide, taking care to avoid loss of bromine, shake thoroughly and titrate with 0.1M sodium thiosulfate VS until only a faint yellow colour remains. Add 0.1 mL of starch mucilage and 10 mL of chloroform and complete the titration with vigorous shaking. Repeat the operation without the injection. The difference between the titrations represents the amount of bromine required. Each mL of 0.05M bromine VS is equivalent to 1.569 mg of C6H6O. Determine the weight per mL of the injection, Appendix V G, and calculate the percentage w/v of C6H6O.
STORAGE
Phenol and Glycerol Injection should be protected from light.
LABELLING
The strength is stated as the percentage w/v of Phenol.
