Vitamin D3

Absorption

Cholecalciferol is readily absorbed from the small intestine if fat absorption is normal . Moreover, bile is necessary for absorption as well .
In particular, recent studies have determined aspects about the absorption of vitamin D, like the fact that a) the 25-hydroxyvitamin D metabolite of cholecalciferol is absorbed to a greater extent than the nonhydroxy form of cholecalciferol, b) the quantity of fat with which cholecalciferol is ingested does not appear to largely affect its bioavailability, and c) age does not apparently effect vitamin D cholecalciferol .

Toxicity

Chronic or acute administration of excessive doses of cholecalciferol may lead to hypervitaminosis D, manifested by hypercalcemia and its sequelae . Early symptoms of hypercalcemia may include weakness, fatigue, somnolence, headache, anorexia, dry mouth, metallic taste, nausea, vomiting, vertigo, tinnitus, ataxia, and hypotonia . Later and possibly more serious manifestation include nephrocalcinosis, renal dysfunction, osteoporosis in adults, impaired growth in children, anemia, metastatic calcification, pancreatitis, generalized vascular calcification, and seizures .
Safety of doses in excess of 400 IU (10mcg) of vitamin D3 daily during pregnancy has not been established . Maternal hypercalcemia, possibly caused by excessive vitamin D intake during pregnancy, has been associated with hypercalcemia in neonates, which may lead to supravalvular aortic stenosis syndrome, the features of which may include retinopathy, mental or growth retardation, strabismus, and other effects . Hypercalcemia during pregnancy may also lead to suppression of parathyroid hormone release in the neonate, resulting in hypocalcemia, tetany, and seizures .
Vitamin D is deficient in maternal milk; therefore, breastfed infants may require supplementation. Use of excessive amounts of Vitamin D in nursing mothers may result in hypercalcemia in infants. Doses of Vitamin D3 in excess of 10 μg daily should not be administered daily to nursing women.

Description

Cholecalciferol, the inactive form of vitamin D3, is found in fish oils and is photosynthesized in human skin by sunlight. It was first prepared in the lab by A. Windaus and co-workers in 1936. Cholecalciferol undergoes two metabolic biochemical reactions that convert it to vitamin D3’s active form, calcitriol, a hormone that mediates intestinal calcium absorption and bone calcium metabolism. Recently, T. Takahashi et al.?improved the synthesis of cholecalciferol?by using a flow microreactor.

Chemical properties

White or colorless crystalline solid. Odorless;

Originator

Vitamin D, Country Life

The Uses of Vitamin D3

Vitamin D3 analogue.

The Uses of Vitamin D3

carnitine replenisher in peripheral arterial disease

The Uses of Vitamin D3

The vitamin that mediates intestinal calcium absorbtion, bone calcium metabolism and probably, muscle activity. Occurs in and is isolated from fish liver oils. Vitamin D acts through a receptor that i s a member of the ligand-dependent transcription factor superfamily. Modulates the proliferation and differentiation of both normal and cancer cells. Has antiproliferative and antimetastatic effects o n breast, colon, and prostate cancer cells. Activated vitamin D receptors in intestine and bone maintain calcium absorbance and homeostasis.

The Uses of Vitamin D3

selective phosphodiesterase-4 inhibitor (PDE-4 inhibitor) under investigation for treating respiratory diseases involving chronic inflammation such as asthma or COPD (smoker’s lung)

The Uses of Vitamin D3

Cholecalciferol and ergocalciferol are used for the control of rats and mice.

What are the applications of Application

Cholecalciferol is an unhydroxylated form of vitamin D3

Indications

Cholecalciferol use is indicated for the treatment of specific medical conditions like refractory rickets (or vitamin D resistant rickets), hypoparathyroidism, and familial hypophosphatemia .
Concurrently, as one of the most commonly utilized forms of vitamin D, cholecalciferol is also very frequently used as a supplement in individuals to maintain sufficient vitamin d levels in the body or to treat vitamin D deficiency, as well as various medical conditions that can be associated directly or indirectly with vitamin d insufficiency like osteoporosis and chronic kidney disease, among others .

Background

Vitamin D, in general, is a secosteroid generated in the skin when 7-dehydrocholesterol located there interacts with ultraviolet irradiation - like that commonly found in sunlight . Both the endogenous form of vitamin D (that results from 7-dehydrocholesterol transformation), vitamin D3 (cholecalciferol), and the plant-derived form, vitamin D2 (ergocalciferol), are considered the main forms of vitamin d and are found in various types of food for daily intake . Structurally, ergocalciferol differs from cholecalciferol in that it possesses a double bond between C22 and C23 and has an additional methyl group at C24 . Finally, ergocalciferol is pharmacologically less potent than cholecalciferol, which makes vitamin D3 the preferred agent for medical use .
Appropriate levels of vitamin D must be upheld in the body in order to maintain calcium and phosphorus levels in a healthy physiologic range to sustain a variety of metabolic functions, transcription regulation, and bone metabolism . However, studies are also ongoing to determine whether or not cholecalciferol may also play certain roles in cancer, autoimmune disorders, cardiovascular disease, and other medical conditions that may be associated with vitamin D deficiency .

Definition

A free vitamin D 3, isolated in crystalline state from the 3,5-dinitrobenzoate, produced by irradiation, and equivalent in activity to vitamin D3 of tunaliver oil.

Indications

Vitamin D is the collective term for a group of compounds formed by the action of ultraviolet irradiation on sterols. Cholecalciferol (vitamin D₃) and calciferol (vitamin D₂) are formed by irradiation of the provitamins 7- dehydrocholesterol and ergosterol, respectively. The conversion to vitamin D3 occurs in the skin. The liver is the principal storage site for vitamin D, and it is here that the vitamin is hydroxylated to form 25-hydroxyvitamin D. Additional hydroxylation to form 1,25-dihydroxyvitamin D occurs in the kidney in response to the need for calcium and phosphate

Indications

Vitamin D₃, through its active metabolite, 1,25- (OH)₂D₃, also plays an important role in maintaining calcium homeostasis by enhancing intestinal calcium absorption, PTH-induced mobilization of calcium from bone, and calcium reabsorption in the kidney.

Manufacturing Process

5 g of 7-dehydrocholesteryl acetate (prepared by W.R. Ness, R. S. Kostic and Mosetting, J. Am. Chem. Soc. 78, 436, 1956) were dissolved in 500 ml of nhexane. This solution was irradiated with ultraviolet ray by recyclicly passing it through a quartz apparatus surrounding 450 w high pressure mercury vapor lamps for 80 minutes. After irradiation and then the distillating off of nhexane the solution was added with 50 ml of ethanol and the ethanolic solution was left to stand overnight at the temperature of -20°C. The formed crystals were filtered off from ethanolic solution and filtrate was heated at the temperature 78°C for 4 hours. After cooling of filtrate, the cooled filtrate was added with 4 ml of ethanolic solution containing 0.7 g of potassium hydroxide to effect a reaction at the temperature of 20°C and under nitrogen for 60 minutes. The reaction product was added with 0.7 ml glacial acetic acid and then ethanol was distilled off under reduced pressure from the reaction product. The obtained residue was extracted with 50 ml of n-hexane and extract was washed with water and n-hexane was distilled off from extract to obtain 2.5 g of yellow oily matter containing vitamin D3. The content of vitamin D3 in yellow oily matter was 40.2% by weight.

Therapeutic Function

Vitamin, Antirachitic

Biosynthesis

The primary supply of vitamin D₃ in humans is not obtained from the diet but rather is derived from the ultraviolet photoconversion of 7-dehydrocholesterol to vitamin D₃ in skin. Thus, vitamin D₃ synthesis varies with the seasons. D₃ is a prohormone and requires further metabolic conversion to exert biological activity in its target organs. The liver and the kidney are the major sites of metabolic activation of this endogenous sterol hormone. The initial transformation of D3 occurs in the liver and is catalyzed by the enzyme 25-OH-D₃-hydroxylase to form 25-(OH)D₃; this is the primary circulating form of D₃. Circulating 25-(OH)D₃ is then converted by the kidney to the most active form of D₃, 1,25-(OH)₂D₃, by the 1-(OH)-D₃-hydroxylase enzyme. Blood concentrations of 1,25-(OH)₂D₃ are approximately one fivehundredth of those of 25-(OH)D₃. 1, 25-(OH)₂D₃ is converted to the metabolite 24R,25-(OH)₂D₃, which is capable of suppressing parathyroid secretion.
In addition to the endogenous metabolites, some exogenous sterols possess biological activity similar to that of D₃. Ergocalciferol (vitamin D₂) is derived from the plant sterol ergosterol and may act as a substrate for both the 25-hydroxylase and the 1-hydroxylase enzyme systems of the liver and kidney to form 25-(OH)D₂ and 1,25-(OH)₂ D₂, respectively. Ergocalciferol (vitamin D₂) is the form used in commercial vitamins and supplemented dairy products. Dihydrotachysterol, another sterol that is used as a therapeutic agent, also functions as a substrate for the hydroxylase enzymes in the liver and kidney.

General Description

Fine colorless crystals. Water insoluble.

Air & Water Reactions

Sensitive to moisture, air and light. . Water insoluble.

Reactivity Profile

Vitamin D3 may react vigorously with strong oxidizing agents. May react exothermically with reducing agents to release hydrogen gas.

Health Hazard

SYMPTOMS: Symptoms of exposure to Vitamin D3 may include weakness, fatigue, lassitude headache, nausea, vomiting, diarrhea, polyuria, polydipsia, nocturia, decrease urinary concentrating ability, proteinuria, tissue calcification, hypertension and osteoporosis.

Fire Hazard

Flash point data for Vitamin D3 are not available. Vitamin D3 is probably combustible.

Agricultural Uses

Rodenticide: Used in bait for vermin control. Vitamin D is a steroid hormone that has an important role in regulating body levels of calcium and phosphorus, and in mineralization of bone. Not approved for use in EU countries. Registered for use in the U.S. and other countries.

Trade name

DELSTEROL®; DEPARAL®; D3- VIGANTOL®; QUINTOX®; RAMPAGE®; RICKETON®; TRIVITAN®; VIGORSAN®; VITINC DAN-DEE-3®

Biochem/physiol Actions

Vitamin D acts through a receptor that is a member of the ligand-dependent transcription factor superfamily. Modulates the proliferation and differentiation of both normal and cancer cells. Has antiproliferative and antimetastatic effects on breast, colon, and prostate cancer cells. Activated vitamin D receptors in intestine and bone maintain calcium absorbance and homeostasis.

Mechanism of action

1, 25-(OH)₂D₃ exerts its influence within target tissues through high-affinity sterol-specific intracellular receptor proteins.The D₃ receptor, similar to steroid receptor systems, translocates the hormone from the cell cytoplasm to the nucleus, where biological response is initiated via transcription and translation.

Pharmacokinetics

The in vivo synthesis of the predominant two biologically active metabolites of vitamin D occurs in two steps. The first hydroxylation of vitamin D3 cholecalciferol (or D2) occurs in the liver to yield 25-hydroxyvitamin D while the second hydroxylation happens in the kidneys to give 1, 25-dihydroxyvitamin D . These vitamin D metabolites subsequently facilitate the active absorption of calcium and phosphorus in the small intestine, serving to increase serum calcium and phosphate levels sufficiently to allow bone mineralization . Conversely, these vitamin D metabolites also assist in mobilizing calcium and phosphate from bone and likely increase the reabsorption of calcium and perhaps also of phosphate via the renal tubules . There exists a period of 10 to 24 hours between the administration of cholecalciferol and the initiation of its action in the body due to the necessity of synthesis of the active vitamin D metabolites in the liver and kidneys . It is parathyroid hormone that is responsible for the regulation of such metabolism at the level of the kidneys .

Clinical Use

The principal disorder associated with inadequate vitamin D intake is rickets. The low blood calcium and phosphate levels that occur during vitamin D deficiency stimulate parathyroid hormone secretion to restore calcium levels. In children, this deficiency leads to the formation of soft bones that become deformed easily; in adults, osteomalacia results from the removal of calcium from the bone.Vitamin D deficiency may occur in patients with metabolic disorders, such as hypoparathyroidism and renal osteodystrophy. The requirement for vitamin D is slightly higher in members of darker-pigmented races, since melanin interferes with the irradiation that produces vitamin D₃ in the skin. People with limited exposure to the sun may need to supplement vitamin D intake.

Side Effects

The hypercalcemia resulting from hypervitaminosis D is responsible for toxic symptoms such as muscle weakness, bone pain, anorexia, ectopic calcification, hypertension, and cardiac arrhythmias. Toxicity in infants can result in mental and physical retardation, renal failure, and death.

Safety Profile

Poison by ingestion. An experimental teratogen. When heated to decomposition it emits acrid smoke and irritating fumes.

Potential Exposure

Sterol rodenticide used in bait for vermin control. Vitamin D is a steroid hormone that has an important role in regulating body levels of calcium and phosphorus, and in mineralization of bone. Not approved for use in EU countries

Drug interactions

Potentially hazardous interactions with other drugs
Antiepileptics: the effects of vitamin D may be reduced in patients taking barbiturates or anticonvulsants.
Diuretics: increased risk of hypercalcaemia with thiazides.
Sevelamer: absorption may be impaired by sevelamer.

Metabolic pathway

Cholecalciferol (vitamin D3) is the mammalian form of vitamin D. It is normally produced in the skin by the action of UV light on its precursor, 7- dehydrocholesterol. Essential amounts of the vitamin are obtained thus or from dietary sources such as fish oils. The active form of the vitamin is 1,25-dihydroxy-cholecalciferol. Its formation occurs in two stages: 25- hydroxylation in the liver, followed by 1-hydroxylation in the kidney (see Engstrom and Koszewski, 1989 and references cited therein).

Metabolism

Within the liver, cholecalciferol is hydroxylated to calcifediol (25-hydroxycholecalciferol) by the enzyme vitamin D-25-hydroxylase . At the kidney, calcifediol subsequently serves as a substrate for 1-alpha-hydroxylase, yielding calcitriol (1,25-dihydroxycholecalciferol), the biologically active form of vitamin D3 .

Metabolism

Within the liver, cholecalciferol is hydroxylated to calcidiol (25-hydroxycholecalciferol) by the enzyme 25-hydroxylase. Within the kidney, calcidiol serves as a substrate for 1-alpha-hydroxylase, yielding calcitriol (1,25-dihydroxycholecalciferol), the biologically active form of vitamin D3.
Cholecalciferol and its metabolites are excreted mainly in the bile and faeces.

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Purification Methods

It is converted into its 3,5-dinitrobenzoyl ester and crystallised repeatedly from acetone. The ester is then saponified and the free vitamin is isolated. [Laughland & Phillips Anal Chem 28 817 1956, Beilstein 6 III 2811, 6 IV 4149.]

Degradation

It is unstable in light and air and in acidic media. It is inactivated within a few days under normal exposure conditions. This is due to oxidation and fragmentation of the triene functionality.

Toxicity evaluation

Another steroidal rodenticide is cholecalciferol, which is in fact the naturally occurring vitamin D3. This compound is an essential factor for vertebrates but in large doses causes hypercalcemia, resulting in calcification and degeneration of various soft tissues, ultimately leading to death. In baits, cholecalciferol may be combined with other, usually anticoagulant, rodenticides. The main natural source of cholecalciferol is fish liver oil, but it is manufactured from ergosterol.

Incompatibilities

Sensitive to air, light, and moisture. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Waste Disposal

Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material’s impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.