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

Specific gravity á841ñ: between 0.914and 0.921.

Heavy metals,Method IIá231ñ: 0.001%.

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 gently until the carbon disulfide is expelled,then immerse the tube to one-third of its depth in a boiling,saturated solution of sodium chloride:no reddish color develops within 15minutes.

Fatty acid composition— Place about 1g of Corn Oil in a small conical flask fitted with a reflux attachment.Add 10mLof methanol and 0.5mLof 1Nmethanolic potassium hydroxide solution prepared by dissolving 34g of potassium hydroxide in sufficient methanol to produce 500mL,allow it to settle for 24hours,and decant the clear solution.Reflux the mixture for 10minutes,cool,transfer to a separator with the aid of 15mLof n-heptane,shake with 10mLof saturated sodium chloride solution,and allow to separate.Transfer the lower layer to another separator,and shake it with 10mLof n-heptane.Wash the combined organic layers with 10mLof water,dry over anhydrous sodium sulfate,and filter.Introduce a suitable portion of the filtrate into a gas chromatograph equipped with a flame-ionization detector and a 4-mm ×1.8-m column,preferably glass,packed with 10%liquid phase G4on support S1A,maintained at a temperature of 175.The carrier gas is nitrogen.Measure the five main peak areas of the methyl esters of the fatty acids.The order of elution is palmitate,stearate,oleate,linoleate,and linolenate,and their relative areas,expressed as percentages of the total area of the 5main peaks,are in the ranges 8to 19,1to 4,19to 50,34to 62,and 1to 2,respectively.

Free fatty acids á401ñ— The free fatty acids in 10.0g require for neutralization not more than 2.0mLof 0.020Nsodium hydroxide.

Iodine value á401ñ: between 102and 130.

Saponification value á401ñ: between 187and 193.

Unsaponifiable matter á401ñ: not more than 1.5%.

Organic volatile impurities,Method IVá467ñ: meets the requirements.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 2991

Phone Number:1-301-816-8262