Packaging and storage— Preserve in tight, light-resistant containers.

Assay for parachlorophenol— Transfer about 1 g of Camphorated Parachlorophenol, accurately weighed, to a wide-mouth conical flask, and add a few glass beads, 6 mL of sodium hydroxide solution (1 in 2), and 130 mL of water. Heat the solution to boiling, add 70 mL of potassium permanganate solution (3 in 50), and continue to boil for 20 minutes. To the hot solution add 40 mL of 0.1 N silver nitrate. Add 50 mL of 18 N sulfuric acid, and sodium sulfite crystals, in divided portions and with swirling until the permanganate color is discharged and no manganese dioxide remains. Boil until the vapors are no longer acid to litmus, keeping the volume nearly constant by the addition of water. Add 5 mL of nitric acid, and continue to boil for 5 minutes. Cool, and collect the precipitate on a tared filtering crucible, wash well with water, then with 10 mL of alcohol, dry at 105 for 1 hour, cool, and weigh. Each 1.000 g of the silver chloride so obtained is equivalent to 897.0 mg of C6H5ClO.

Assay for camphor— Transfer about 300 mg of Camphorated Parachlorophenol, accurately weighed, to a 200-mL pressure bottle containing 50 mL of freshly prepared dinitrophenylhydrazine TS. Close the pressure bottle, immerse it in a water bath, and maintain it at about 75 for 4 hours. Cool to room temperature, then transfer the contents to a beaker with the aid of 100 mL of 3 N sulfuric acid and allow it to stand overnight. Collect the precipitate on a tared filtering crucible, wash with 100 mL of 3 N sulfuric acid and then with 75 mL of cold water, in divided portions, to remove the acid. Dry at 80 for 2 hours, cool, and weigh. The weight of the precipitate so obtained, multiplied by 0.4581, represents the weight of C10H16O in the sample taken.

Topic/Question	Contact	Expert Committee
Monograph	Behnam Davani, Ph.D., M.B.A. Senior Scientist 1-301-816-8394	(MDAA05) Monograph Development-Antivirals and Antimicrobials

USP32–NF27 Page 3207