Cholecalciferol

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Cholecalciferol
IUPAC name	(3β,5Z,7E)-9,10- secocholesta-5,7,10(19)-trien-3-ol
Other names	vitamin D3, activated 7-dehydrocholesterol.
Identifiers
CAS number	[67-97-0]
Properties
Molecular formula	C27H44O
Molar mass	384.64 g/mol
Appearance	White, needle-like crystals
Melting point	83–86 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Cholecalciferol is a form of Vitamin D, also called vitamin D₃.

7-Dehydrocholesterol is the precursor of vitamin D₃ and only forms the vitamin after being exposed to UV radiation.

After exposure to the sun, cholecalciferol is sent to the liver to be hydroxylated where it becomes 25-Hydroxyvitamin D₃.

Next, it is sent to the kidney and once again hydroxylated becoming 1,25-Hydroxyvitamin D₃. 1,25-Hydroxyvitmain D₃ is the active hormone form of vitamin D₃, for this reason vitamin D is often referred to as a prohormone.

It is structurally similar to steroids such as testosterone, cholesterol, and cortisol (though vitamin D₃ itself is a secosteroid).

1g of pure vitamin D₃ is 40 000 000 (40x10⁶) IU, or in other words, one IU is 0.025 μg.

Cholecalciferol is the form of vitamin D normally added during fortification of foods. In most countries it is mandatory to fortify margarine products with vitamin D in order to make them more nutritionally similar to butter. Cholecalciferol is produced industrially by the irradiation of 7-dehydrocholesterol extracted from lanolin found in sheep's wool. In products where animal products are not desired, such as for vegetarians or markets where there are religious concerns such as India, the alternative is to use ergocalciferol (also known as vitamin D₂) derived from the fungal sterol ergosterol.

A 2004 study showed that, while the absorption of cholecalciferol and ergocalciferol is approximately equivalent in healthy individuals, cholecalciferol is three to ten times more potent than ergocalciferol, and has more prolonged effects.^[1]

[edit] Stability

Cholecalciferol is very sensitive to UV radiation and will rapidly, but reversibly break down to form supra-sterols, which can further irreversibly convert to tachysterol.

[edit] References