QUANTITATIVE DETERMINATION OF VITAMIN A and E

QUANTITATIVE DETERMINATION OF VITAMIN A AND VITAMIN E:

QUANTITATIVE DETERMINATION OF VITAMIN A AND VITAMIN E BY P.Sravanthi M.pharmacy 1styear-pharmaceutical analysis TRINITY college of pharmaceutical sciences

VITAMINS:

VITAMINS Vitamins are naturally occurring organic compounds that are essential to metabolic or other functions in the body. Most vitamins cannot be synthesized by the body. They must be supplied in the diet. Vitamins are usually classified as water soluble or fat soluble

CLASSIFICATION OF VITAMINS:

CLASSIFICATION OF VITAMINS Vitamins can be classified as either Water soluble Fat soluble. Water soluble vitamins are generally involved in the cellular metabolism of energy supplying nutrients. Fat soluble vitamins often have very specialized functions

Water Soluble Vitamins:

Water Soluble Vitamins Examples of water soluble vitamins Vitamin C Vitamin B 1 (Thiamine)

Fat Soluble Vitamins:

Fat Soluble Vitamins Common fat soluble vitamins include A, D , vitamin A E, K.

Vitamin A Sources:

Vitamin A Sources Commonly found in cod liver oil, green vegetables, and fruits. Carrots indirectly serve as a source of vitamin A since they contain β carotene which the body readily converts to vitamin A

Vitamin A Functions:

Vitamin A Functions Vitamin A is fat soluble. It is not readily broken down by cooking. Role in aiding in night vision. Vitamin A Deficiencies A deficiency in vitamin A results in night blindness. The most serious deficiency results in a condition known as Xeropthalmia, a severe form of conjunctivitis or blindness.

Vitamin E sources:

Vitamin E sources vitamin E can be found most abundantly in wheat germ oil, sunflower, and safflower oils and also in nuts, cereals, olive, tomato, spinach, blue crab. olive nuts cereals

Vitamin E functions:

Vitamin E functions Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols . α- Tocopherol is an important lipid-soluble antioxidant. α- Tocopherol has a regulatory effect on enzymatic activities responsible for the repair of the wounds and regeneration of the extracellular tissue, vitamin E also plays a role in neurological functions, and inhibition of platelet aggregation

Quantitative determination of vitamin A:

Quantitative determination of vitamin A Category: antixerophthalmic vitamin Structure: Standards: not less than 95% and not more than 110% of standard number of units of vitamin A per g.

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Identification: exhibits a maximum at about 325- 327nm. QUANTITATIVE ESTIMATION METHOD: UV- Spectrophotometric method principle: it absorbs the UV-radiation ranges from 200nm to 400nm. Valence electrons absorb the energy, there by molecule undergo transition from ground state to excited state. By the absorption peaks the nature of electrons and molecular structure can be elucidated.

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METHOD: Dissolve an accurately weighed quantity of the substance in cyclohexane to give a solution containing 9 to 15 units of vit A per ml. Determine the wave length of maximum absorption. Measure the absorbance of the solution against cyclo hexane at 328 nm. If the wave length of maximum absorption lies between 326 and 329 calculate the vit A potency of the sample from the expression A328(A 1% 1cm ) × 1900 = vit A potency in units per g.

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If the relative absorbances are not within the limits then calculate a corrected absorbance at about 328nm by applying the observed values to the equation A328(corr.) = 3.52 (2A328 –A316 – A 340) If the wavelength of maximum absorbance lies out side the range of 323 to 327 then the unsaponifiable fraction of the sample must be further purified by chromatography.

Quantitative determination of vitamin E:

Quantitative determination of vitamin E Category: anti oxidant Structure: Standards: it contains not less than 96% and not more than 102% of C31H52O3.

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QUANTITATIVE ESTIMATION METHOD: Chromatographic method: Principle: The principle of separation in GAS CHROMATOGRAPHY is partition. They travel according to their partition coefficients towards the stationary phase. More soluble travels slower Less soluble travels faster No two components have same partition coefficients. The components are separated according to their partition coefficients.

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METHOD: Internal standard solution: dissolve an accurately weighed quantity of hexa decyl hexa decanoate in n-hexane to obtain a solution having a known concentration of about 1mg per ml. Standard preparation: dissolve in internal standard solution a suitable quantity of USP alpha tocopherol RS to obtain a solution having known concentration of 1mg per ml. Assay preparation: transfer 50mg of vitamin E to a 50ml volumetric flask, dissolve in internal standard solution, dilute with internal standard solution to volume and mix.

Chromatographic system:

Chromatographic system The GC instrument is equipped with a flame ionization detector. It contains 2m-4mm borosilicate glass column packed with 2% to 5% liquid phase on 80 to 100 mesh support utilizing a column injection. The column is maintained at a temp. between 245° to 265°

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The injection port and detector block are maintained at about 10° higher than the column temperature. The flow rate of dry carrier gas is adjusted to obtain a peak approximately 18 to 20 min after sample introduction. Procedure: Inject a suitable portion (2-5µl) of the assay preparation into a suitable gas chromatograph. Record the chromatogram . Measure the areas under the 1 st (alpha tocopherol ) and 2 nd major( hexadecyl hexa decanoate )peaks, record the values as a U and a D respectively. Calculate the quantity in mg, of vit E taken by the formula (50C D /F)(a U / a D ) Where C D is conc.in mg/ml F is the relative response factor

REFERENCES:

REFERENCES INDIAN PHARMACOPOEIA BRITISH PHARMACOPOEIA UNITED STATES PHARMACOPOEIA www.googleimages.com www.wikipedia.com www.cyberlipid.org

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