Packaging and storage— Preserve in tight containers.

Specific gravity á841ñ: between 0.988and 0.993.

Distilling range,Method Iá721ñ: between 138.5and 142.5.

Heavy metals á231ñ— To the residue obtained in the test for Nonvolatile residueadd 8mLof 0.1Nhydrochloric acid,warm gently until solution is complete,dilute with water to 100mL,and use 10mLof the solution:the limit is 0.001%.

Limit of nonvolatile residue— Evaporate 20g in a tared dish,and dry at 105for 1hour:the weight of the residue does not exceed 2.0mg.

Readily oxidizable substances— Dissolve 15g of sodium hydroxide in 50mLof water,cool,add 6mLof bromine,stirring to effect complete solution,and dilute with water to 2000mL.Transfer 25.0mLof this solution to a glass-stoppered,250-mLconical flask containing 100mLof water,and add 10mLof sodium acetate solution (1in 5)and 10.0mLof Propionic Acid.Allow to stand for 15minutes,add 5mLof potassium iodide solution (1in 4)and 10mLof hydrochloric acid,and titrate with 0.1Nsodium thiosulfate VSjust to the disappearance of the brown color.Perform a blank determination.The difference between the volume of 0.1Nsodium thiosulfate required for the blank and that required for the test specimen is not more than 2.2mL.

Limit of aldehydes— Transfer 10.0mLto a glass-stoppered,250-mLconical flask containing 50mLof water and 10.0mLof sodium bisulfite solution (1in 80),insert the stopper,and shake vigorously.Allow the mixture to stand for 30minutes,then titrate with 0.1Niodine VSto the same brownish yellow endpoint obtained with a blank treated with the same quantities of the same reagents.The difference between the volume of 0.1Niodine required for the blank and that required for the test specimen is not more than 1.75mL.

Organic volatile impurities,Method Iá467ñ: meets the requirements.

Assay— Mix about 1.5g of Propionic Acid,accurately weighed,with 100mLof recently boiled and cooled water in a 250-mLconical flask,add phenolphthalein TS,and titrate with 0.5Nsodium hydroxide VSto the first appearance of a faint pink endpoint that persists for not less than 30seconds.Each mLof 0.5Nsodium hydroxide is equivalent to 37.04mg of C3H6O2.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3067

Phone Number:1-301-816-8262