Alpha tocopherol

• BPAlpha Tocopherol
• JPTocopherol
• Ph. Eur.all-rac-α-Tocopherol
• USP–NFVitamin E

all-rac-α-tocopherol; dl-α-tocopherol; RRR-α-tocopherol (d-α-tocopherol); synthetic or natural vitamin E; E307

(2RS)-2,5,7,8-Tetramethyl-2-[(4RS,8RS)-4,8,12-trimethyltridecyl]-3,4-dihydro-2H-1-benzopyran-6-ol (all-rac form) · [10191-41-0]

UNII 7QWA1RIO01 · PubChem CID 2116

C29H50O2 · 430.71

Antioxidant, chelating agent

Typical concentrations: — · Dosage forms: Liquid, Semi-solid, Solid

Used as a lipophilic antioxidant in oils, fats, oily injections, soft capsules, emulsions, ointments and other lipid-based formulations, usually at about 0.001–0.05% w/v. It is also the active form of vitamin E in supplements and nutritional products, and it is used as an oil phase or solubiliser in some self-emulsifying and parenteral emulsion systems.

A practically odourless, clear, yellow or greenish-yellow, viscous oil. Synthetic all-rac-α-tocopherol is an equimolar mixture of eight stereoisomers; natural RRR-α-tocopherol is a single stereoisomer.

Density

≈ 0.95 g/cm³

Refractive index

≈ 1.503–1.507

Appearance

viscous oil; may become partly solid at low temperature

Solubility

practically insoluble in water; freely soluble or miscible with acetone, ethanol, ether, fatty oils and vegetable oils

Oxidised slowly by atmospheric oxygen and more rapidly in the presence of ferric and silver salts; it darkens on exposure to light. Store under an inert gas in an airtight container, protected from light, in a cool place. The esters (such as tocopheryl acetate) are much more stable but have no antioxidant activity in the formulation.

Incompatible with peroxides and other oxidising agents and with metal ions, especially iron, copper and silver, which catalyse its oxidation. It may be absorbed by some plastics.

Natural RRR-α-tocopherol is obtained from vegetable oil distillates (for example soybean oil deodoriser distillate), often with methylation of other tocopherols to the alpha form. Synthetic all-rac-α-tocopherol is made by condensing trimethylhydroquinone with isophytol.

Well tolerated at the levels used as an excipient. Very high oral intakes over long periods may increase bleeding tendency, particularly with anticoagulants; EFSA has set a tolerable upper intake level of 300 mg/day for adults. Topical use occasionally causes contact dermatitis.

Observe normal precautions for the quantity handled. Gloves and eye protection are recommended. Minimise air exposure during dispensing, for example by blanketing with nitrogen.

GRAS listed. Accepted as a food additive in Europe (E307 for alpha-tocopherol). Included in the FDA Inactive Ingredient Database (intravenous injections, oral capsules and tablets, and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

d-α-Tocopherol (RRR); dl-α-tocopheryl acetate; d-α-tocopheryl acid succinate; tocopherols excipient (mixed tocopherols); tocopheryl polyethylene glycol succinate (vitamin E TPGS).

Alpha tocopherol works synergistically with ascorbyl palmitate or ascorbic acid, which regenerate it, and with chelating agents. For use purely as an antioxidant, mixed tocopherols are often more effective than alpha tocopherol alone.