Vitamin E Polyethylene Glycol Succinate
» Vitamin E Polyethylene Glycol Succinate is a mixture formed by the esterification of d-alpha tocopheryl acid succinate and polyethylene glycol. The ester mixture consists primarily of the mono-esterified polyethylene glycol and a small amount of di-esterified polyethylene glycol. It contains not less than 25.0 percent of d-alpha tocopherol (C29H50O2).
Packaging and storage Preserve in tight containers, protected from light.
Labeling The labeling indicates the d-alpha tocopherol content, expressed in mg per g.
Identification The retention time of the major peak in the chromatograph of the Test solution corresponds to that in the chromatogram of the Standard solution, as obtained in the test for Content of alpha tocopherol.
Solubility in water Place 20 g of melted Vitamin E Polyethylene Glycol Succinate in a glass container on a magnetic stirrer. Immediately add 80 mL of boiling water, while stirring. Allow to cool to room temperature with constant stirring. The solution becomes clear within 3 hours.
Acid value Dissolve 1.0 g of it in 25 mL of a mixture of alcohol and ether (1:1) that has been neutralized to phenolphthalein with 0.1 N sodium hydroxide. Add 0.5 mL of phenolphthalein TS, and titrate with 0.10 N sodium hydroxide until the solution remains faintly pink after shaking for 30 seconds: not more than 0.27 mL of 0.10 N sodium hydroxide is consumed.
Specific rotation 781S: not less than +24.0. [noteThis test identifies d-alpha tocopherol after saponification.]
Test solution Transfer about 0.9 g of Vitamin E Polyethylene Glycol Succinate, molten at 60, accurately weighed, to a suitable test tube fitted with a cap, and dissolve in 10.0 mL of alcohol. Place the tube in a heating block set between 100 and 105. [noteSolution is to reflux gently without emission of contents.] When sample is fully dissolved, add 2 to 3 pellets of sodium hydroxide, and continue to reflux for an additional 30 minutes. Remove the tube from the heat and while contents are still hot, neutralize using phenolphthalein as the indicator by slowly adding 10 mL of a mixture of water and hydrochloric acid (1:1) until the pink color disappears. [CautionExothermic 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 25.0 mL of heptane, cap, and shake for 1 minute 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 10.0 mL of water to the recovered solution. Cap, shake, and allow layers to separate. Transfer the upper layer to a clean dry tube. Add 10.0 mL of potassium ferricyanide solution, prepared by dissolving 2 g of potassium ferricyanide in 10.0 mL of 0.2 M sodium hydroxide, and replace the cap. Shake vigorously for 45 seconds, and allow the layers to separate for 30 minutes. 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. [noteUse the results of the test for Content of alpha tocopherol below to calculate the specific rotation.]
Content of alpha tocopherol
Solvent Mix 0.25 mL of phenolphthalein TS with 1 L of alcohol.
Internal standard solution Dissolve an accurately weighed quantity of ethyl arachidate in isooctane to obtain a solution having a concentration of about 12 mg per mL.
Standard solution Transfer about 32.5 mg of USP Alpha Tocopherol RS, accurately weighed, to a suitable reaction flask. Add 2 mL of pyridine and 0.5 mL of N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane, and heat the flask at 100 for 10 minutes. Cool the flask, add 5.0 mL of Internal standard solution followed by 20 mL of isooctane, and shake.
Test solution Transfer an accurately weighed quantity, between 0.100 and 0.160 g, of Vitamin E Polyethylene Glycol Succinate molten at 60 to a culture tube (about 20 cm long and 2.5 cm in diameter) with a screw cap. Add 40 to 50 mg of ascorbic acid and a few boiling chips followed by 20 mL of Solvent. Place the tube in a heating block set between 100 and 150. [noteSolution is to reflux gently without emission of contents.] When sample is fully dissolved add 0.25 g of potassium hydroxide and continue to reflux for 30 minutes. Remove the tube from heat and while contents are still hot, add 1 to 2 mL of hydrochloric acid dropwise until the pink coloration disappears. [CautionExothermic 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 20 mL of water. Add 5.0 mL of Internal standard solution, cap, and shake to ensure thorough mixing. Allow the tube to stand until two distinct layers are formed. Transfer 2.5 to 3.5 mL of the upper layer into a suitable reaction flask, and add 2.0 mL of pyridine followed by 2.5 mL of N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane. Heat the flask at 100 for 10 minutes. Cool, and then add 12 mL of isooctane.
Chromatographic system (see Chromatography 621) 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 280 and 345, respectively. The column temperature is programmed to rise at a rate of 20 per minute from 260 at the time of injection to 340, where it is held for 1 minute. The carrier gas is helium flowing at a rate of 1.5 mL per minute, and the split flow is about 300 mL per 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 1 µL) of the Standard solution and the Test solution into 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:
100 (M/W)(RU / RS)in which M is the weight, in mg, of USP Alpha Tocopherol RS, used to prepare the Standard solution; W is the weight, in mg, of the Vitamin E Polyethylene Glycol Succinate taken to prepare the Test solution; and RU and RS are the peak response ratios of alpha tocopherol to the internal standard obtained from the Test solution and the Standard solution, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 1376Pharmacopeial Forum: Volume No. 28(6) Page 1909
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.