Packaging and storage— Preserve in tight containers of glass or plastic,containing not more than 15mL,protected from light.The container or individual carton is sealed and tamper-proof so that sterility is ensured at time of first use.

USP Reference standards á11ñ— USP Glycerin RS.

Identification— It responds to the Identificationtest under Glycerin.

Sterility á71ñ: meets the requirements.

pHá791ñ: between 4.5and 7.5,determined potentiometrically in a solution prepared by the addition of 5mLof Sodium Chloride Injection to 5mLof Ophthalmic Solution.

Water,Method Iá921ñ: not more than 1.0%.

Assay— Transfer an accurately measured volume of Ophthalmic 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 Ophthalmic Solution,and note the difference in volumes required.Each mLof 0.1Npotassium arsenite is equivalent to 2.303mg of glycerin (C3H8O3).

Expert Committee:(PA6)Pharmaceutical Analysis 6

USP28–NF23Page 912

Phone Number:1-301-816-8389