Packaging and storage— Preserve in tight,light-resistant containers,and prevent exposure to excessive heat.

Identification— Saponify 5g by boiling with 2.5mLof 7.5Nsodium hydroxide and 12.5mLof alcohol.Evaporate the alcohol,dissolve the soap in 50mLof hot water,and add hydrochloric acid until the free fatty acids separate as an oily layer.Cool the mixture,and remove the separated fatty acids and dissolve them in 75mLof ether.To the ether solution add a hot solution of 4g of lead acetate in 40mLof alcohol,and allow the mixture to stand for 18hours.Filter the supernatant,and transfer the precipitate to the filter with the aid of ether.Place the precipitate in a mixture of 40mLof 3Nhydrochloric acid and 20mLof water,and heat until the oily layer is entirely clear.Cool,decant the water solution,and boil the fatty acids with water that has been acidified with hydrochloric acid,until free from lead.(The fatty acids are free from lead when 100mg,dissolved in 10mLof alcohol,is not darkened by the addition of 2drops of sodium sulfide TS.)Allow the fatty acids to solidify,and press them dry between filter papers on a cold surface.Dissolve the solid fatty acids in 25mLof 90percent alcohol,by heating gently,then cool to 15and maintain at that temperature until the fatty acids have crystallized.Filter the separated fatty acids,recrystallize them from hot 90percent alcohol,and dry in a vacuum desiccator for 4hours:the arachidic acid so obtained melts between 73and 76.

Specific gravity á841ñ: between 0.912and 0.920.

Cottonseed oil— Mix 5mLin a test tube with 5mLof a mixture of equal volumes of amyl alcohol and a 1in 100solution of sulfur in carbon disulfide,warm the mixture carefully until the carbon disulfide is expelled,and immerse the test tube to one-third of its length in a boiling,saturated solution of sodium chloride:no reddish color develops within 15minutes.

Rancidity— Shake 1mLof a 1in 10solution of Peanut Oil in ether with 1mLof hydrochloric acid,and add 1mLof a 1in 1000solution of phloroglucinol in ether:no red or pink color develops.

Solidification range of fatty acids á401ñ— The dry mixed fatty acids of it solidify between 26and 33.

Free fatty acids á401ñ— The free fatty acids in 10g require for neutralization not more than 2.0mLof 0.020Nsodium hydroxide.

Iodine value á401ñ: between 84and 100.

Saponification value á401ñ: between 185and 195.

Unsaponifiable matter á401ñ: not more than 1.5%.

Refractive index á831ñ: between 1.462and 1.464at 40.

Heavy metals,Method IIá231ñ: 0.001%.

Organic volatile impurities,Method IVá467ñ: meets the requirements.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3046

Phone Number:1-301-816-8262