Test solution— Transfer about 0.9g of Vitamin E Polyethylene Glycol Succinate,molten at 60,accurately weighed,to a suitable test tube fitted with a cap,and dissolve in 10.0mLof alcohol.Place the tube in a heating block set between 100and 105.[NOTE—Solution is to reflux gently without emission of contents.]When sample is fully dissolved,add 2to 3pellets of sodium hydroxide,and continue to reflux for an additional 30minutes.Remove the tube from the heat and while contents are still hot,neutralize using phenolphthalein as the indicator by slowly adding 10mLof a mixture of water and hydrochloric acid (1:1)until the pink color disappears.[Caution—Exothermic reaction.Allow the acid solution to trickle down the inside of the tube to prevent splashing. ]Cool the tube,cap,and shake until contents are well mixed.Add 25.0mLof heptane,cap,and shake for 1minute to ensure thorough mixing.Allow the tube to stand until two distinct layers are formed.Remove the top layer to a clean dry culture tube,then add 10.0mLof water to the recovered solution.Cap,shake,and allow layers to separate.Transfer the upper layer to a clean dry tube.Add 10.0mLof potassium ferricyanide solution,prepared by dissolving 2g of potassium ferricyanide in 10.0mLof 0.2Msodium hydroxide,and replace the cap.Shake vigorously for 45seconds,and allow the layers to separate for 30minutes.If the top heptane layer is clear,proceed with the measurement for specific rotation;if not clear,dry over anhydrous sodium sulfate before proceeding with the test.[NOTE—Use the results of the test for Content of alpha tocopherolbelow to calculate the specific rotation.]

Solvent— Mix 0.25mLof phenolphthalein TSwith 1liter of alcohol.

Internal standard solution— Dissolve an accurately weighed quantity of ethyl arachidate in isooctane to obtain a solution having a concentration of about 12mg per mL.

Standard solution— Transfer about 32.5mg of USP Alpha Tocopherol RS,accurately weighed,to a suitable reaction flask.Add 2mLof pyridine and 0.5mLof N,O-bis(trimethylsilyl)trifluoroacetamide with 1%trimethylchlorosilane,and heat the flask at 100for 10minutes.Cool the flask,add 5.0mLof Internal standard solutionfollowed by 20mLof isooctane,and shake.

Test solution— Transfer an accurately weighed quantity,between 0.100and 0.160g,of Vitamin E Polyethylene Glycol Succinate molten at 60to a culture tube (about 20cm long and 2.5cm in diameter)with a screw cap.Add 40to 50mg of ascorbic acid and a few boiling chips followed by 20mLofSolvent.Place the tube in a heating block set between 100and 150.[NOTE—Solution is to reflux gently without emission of contents.]When sample is fully dissolved add 0.25g of potassium hydroxide and continue to reflux for 30minutes.Remove the tube from heat and while contents are still hot,add 1to 2mLof hydrochloric acid dropwise until the pink coloration disappears.[Caution—Exothermic reaction.Allow the acid to trickle down the inside of the tube to prevent splashing. ]Cool the tube,then wash the sides of the tube with 20mLof water.Add 5.0mLof Internal standard solution,cap,and shake to ensure thorough mixing.Allow the tube to stand until two distinct layers are formed.Transfer 2.5to 3.5mLof the upper layer into a suitable reaction flask,and add 2.0mLof pyridine followed by 2.5mLof N,O-bis(trimethylsilyl)trifluoroacetamide with 1%trimethylchlorosilane.Heat the flask at 100for 10minutes.Cool,and then add 12mLof isooctane.

Chromatographic system(see Chromatography á621ñ)— The gas chromatograph is equipped with a split injector,a flame-ionization detector,and a 0.25-mm ×15-m fused-silica capillary column coated with a 0.25-µm film of phase G27.The injection port and detector temperatures are maintained at 280and 345,respectively.The column temperature is programmed to rise at a rate of 20per minute from 260at the time of injection to 340,where it is held for 1minute.The carrier gas is helium flowing at a rate of 1.5mLper minute,and the split flow is about 300mLper minute.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the tailing factor for the analyte peak is not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%for the ratio of the alpha tocopherol response to the internal standard response.

Procedure— Separately inject equal volumes (about 1µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of alpha tocopherol,C29H50O2,in the portion of Vitamin E Polyethylene Glycol Succinate taken by the formula: in which Mis the weight,in mg,of USP Alpha Tocopherol RS,used to prepare theStandard solution;Wis the weight,in mg,of the Vitamin E Polyethylene Glycol Succinate taken to prepare the Test solution;and RUand RSare the peak response ratios of alpha tocopherol to the internal standard obtained from the Test solutionand the Standard solution,respectively.