DEFINITION
Oily Phenol Injection is a sterile solution containing 5% w/v of Phenol in a suitable fixed oil.
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.
ASSAY
Dissolve 8 g in 50 mL of ether and extract with successive 10 mL quantities of 2M sodium hydroxide until extraction is complete, boil the combined extracts for 2 minutes, cool and dilute to 250 mL with water. To 20 mL of this solution in a glass-stoppered flask add 30 mL of 0.05M bromine VS and 6 mL of hydrochloric acid, stopper, shake repeatedly during 15 minutes and allow to stand for a further 15 minutes. Add 30 mL of dilute potassium iodide solution, taking care to avoid
loss of bromine, and titrate the liberated iodine with 0.1M sodium thiosulfate VS. 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, Appendix V G, and calculate the percentage w/v of C6H6O.
