Packaging and storage— Preserve in tight containers.

Identification— Heat a few drops with about 500mg of potassium bisulfate in a test tube:pungent vapors of acrolein are evolved.

pHá791ñ: between 5.5and 7.5.

Assay— Transfer an accurately measured volume of Oral Solution,equivalent to about 3g of glycerin,to a 500-mLvolumetric flask,dilute with water to volume,and mix.Transfer a 3-mLportion to a conical flask,add 100.0mLof a solution of potassium periodate (prepared by dissolving 3g of potassium periodate in about 500mLof warm water,cooling to room temperature,and then diluting with water to 1000mL),swirl,and allow to stand at room temperature for 10minutes.Add 4g of sodium bicarbonate and 2g of potassium iodide,and titrate immediately with 0.1Npotassium arsenite VS,adding 3mLof starch TSas the endpoint is approached.Perform a blank determination,using water in place of the Oral Solution,and note the difference in volumes required.Each mLof 0.1Npotassium arsenite is equivalent to 2.303mg of glycerin (C3H8O3).

Expert Committee:(PA4)Pharmaceutical Analysis 4

USP28–NF23Page 912

Phone Number:1-301-816-8251