STP FOR VITAMIN E LIQUID

nirvesh400
  • Description: Clear, colourless or slightly greenish-yellow, viscous, oily liquid.
  • Solubility: Practically insoluble in water, freely soluble in acetone, in anhydrous ethanol  and  in fatty oils.
  • Identification:
  1. Optical rotation : -0.01° to + 0.01°.

Dissolve 2.50 g in anhydrous ethanol R and dilute to 25.0 mL with the same solvent.

  1. B. Infrared absorption spectrophotometry

Comparison a.-tocopheryl acetate CRS.

  1. Thin-layer chromatography

Test solution  Dissolve about 10 mg of the substance to be examined in 2 mL of cyclohexane  R.

Reference solution Dissolve about 10 mg of α-tocopheryl acetate CRS in 2mL of cyclohexane R.

Plate TLC silica gel F 254 plate R.

Mobile phase ether R, cyclohexane R (20:80 V/V).

Application 10 µL

Development  Over 2/3 of the plate.

Drying  In a current of air.

Detection  Examine in ultraviolet light at 254 nm.

Results The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution.

 Tests

  • Related Substances

Gas chromatography : use the normalization procedure.

Internal standard solution :On Dissolve 1.0 g of squalane R in cyclohexane R and dilute to 100.0 mL with the same solvent.

Test solution (a) Dissolve 0.100 g of the substance to be examined in 10.0 mL of the internal standard solution.

Test solution (b) Dissolve 0.100 g of the substance to be examined in 10 mL of cyclohexane

Reference solution (a)  Dissolve 0.100 g of α-tocopheryl acetate CRS in 10.0 mL of

the internal standard solution.

Reference solution (b) Dissolve 10 mg of the substance to be examined and 10 mg of all-rac

– α-tocopherol R in cyclohexane R and dilute to 100.0 mL with the same solvent.

Reference solution (c) Dissolve 10 mg of all-rac- α -tocopheryl acetate for peak

identification CRS (containing impurities A and B) in cyclohexane R and dilute to 1 mL

with  the same solvent.

Reference solution (d) Dilute 1.0 mL of test solution (b) to 100.0 mL with cyclohexane.

Dilute 1.0 mL of this solution to 10.0 mL with cyclohexane R.

Column:

– material: fused silica

– size: l = 30 m, Ø= 0.25 mm

– stationary phase: poly(dimethyl)siloxane R (film thickness 0.25 um).

Carrier gas helium for chromatography R.

Flow rate 1 ml/min.

            Split ratio 1:100.

Temperature:

– column: 280°C;

– injection port and detector: 290°C.

Detection Flame :ionisation.

             Injection 1 µL of test solution (b) and reference solutions (a), (b), (c) and (d); inject

directly onto the column or via a sufficiently inert, glass-lined injection port using an

automatic  injection device or other   reproducible injection method.

            Run time Twice the retention time of all-rac-α-tocopheryl acetate.

Identification of impurities Use the chromatogram supplied with all-rac-α-tocopheryl

acetate for peak identification CRS and the chromatogram obtained with reference solution

(c) to identify the peaks due to impurities A and B.

               Relativeretention With reference to all-rac-α-tocopheryl acetate (retention time =about

15  min):squalane =about 0.4; impurity A =about 0.7; impurity B =about 0.8; impurity C

=   about 0.9;impurities D and E =about 1.05 (eluting immediately after the all-rac-α

– tocopheryl acetate peak).

              System suitability:

– resolution: minimum 3.5 between the peaks due to impurity C and all-rac-α-tocopheryl

acetate in the chromatogram obtained with reference solution (b);

– in the chromatogram obtained with reference solution (a),the area of the peak due to

impurity C is not greater than 0.2 per cent of the area of the peak due to all-rac-α-

tocopheryl  acetate.

            Limits:

– impurities A, C: for each impurity, maximum 0.5 per cent

–  impurity B: maximum 1.5 per cent

– sum of impurities D and E: maximum 1.0 per cent

– any other impurity: for each impurity, maximum 0.25 per cent

– total: maximum 2.5 per cent

– disregard limit: the area of the principal peak in the chromatogram obtained with

reference  solution (d) per cent).

Assay

Gas chromatography  as described in the test for related substances with the

following   modifications.

Injection Test solution (a) and reference solution (a).

System suitability Reference solution (a):

– symmetry factor. minimum 0.6 for the principal peak.

Calculate the percentage content of C31H5203 from the declared content of α-tocopheryl acetate .

STP