Calcitriol

Introduction

Calcitriol (1,25-dihydroxylcholecaldiferol,32222-06-3) is a steroid hormone with three hydroxyl groups, which is an active metabolite and the most effective form of vitamin D. It is produced primarily in the kidney when the blood calcium level and parathyroid hormone are low. Calcitriol promotes the calcium and phosphorus absorption in the intestine, reabsorption in the kidneys. Along with parathyroid hormone, it regulates bone growth for building and keeping strong bones. Calcitriol is used to treat and prevent low levels of calcium and bone disease in patients whose kidneys or parathyroid glands are not working normally, to treat secondary hyperparathyroidism and metabolic bone disease in people with kidney disease. Calcitriol may also be chemopreventive for colon and prostate cancers as it induces cell cycle arrest, cell differentiation, and apoptosis.

References

1. https://pubchem.ncbi.nlm.nih.gov
2. https://medlineplus.gov
3. http://flexikon.doccheck.com/en/Calcitriol
4. https://en.wikipedia.org/wiki/Calcitriol
5. https://www.webmd.com

Description

Calcitriol is the active form of vitamin D and is also a kind of hormones in the body. It plays an important role in the regulation of calcium and phosphorus concentration. It can increase the blood calcium level by increasing the intestinal absorption of calcium and can also increase the release of the bone calcium release for increasing the blood calcium levels. Plasma levels of calcitriol range from 10-70 pg/ml. Clinically, this drug can be used in the treatment of hypocalcemia, hypoparathyroidism (adult), osteomalacia, rickets (infants), chronic kidney disease, renal osteodystrophy, osteoporosis, as well as the prevention of glucocorticoid induced osteoporosis.

Calcitriol-dimensional molecular structure
The above information is edited by the chemicalbook of Dai Xiongfeng.

Chemical Properties

White Crystalline Powder

Originator

Rocaltrol,Roche,US,1978

Uses

Calcitriol is the biologically active form of vitamin D3, and its primary physiological effects are to increase calcium absorption by intestinal epithelial cells and increase bone mineralization by directly stimulating osteoblasts. It is therefore also used as a calcium regulator to treat symptoms of low calcium levels caused by kidney disease. It can also treat parathyroid disease. Calcitriol can regulate parathyroid levels by increasing the amount of calcium (vitamin D) in the body.

Definition

ChEBI: Calcitriol is a hydroxycalciol that is calcidiol in which the pro-S hydrogen of calcidiol is replaced by a hydroxy group. It is the active form of vitamin D3, produced fom calciol via hydoxylation in the liver to form calcidiol, which is subsequently oxidised in the kidney to give calcitriol. It has a role as a bone density conservation agent, an antipsoriatic, an immunomodulator, an antineoplastic agent, a calcium channel modulator, a nutraceutical, a calcium channel agonist, a metabolite, a hormone, a human metabolite and a mouse metabolite. It is a hydroxycalciol, a member of D3 vitamins and a triol.

Manufacturing Process

1α,25-Dihydroxyprecholecalciferol: A solution of 1α,25- diacetoxyprecholecalciferol (0.712 g, 1.42 mmols), potassium hydroxide (2.0 g, 35.6 mmols) and methanol (40 ml) was stirred at room temperature under argon for 30 hours. The reaction mixture was concentrated under reduced pressure. Water (50 ml) was added to the residue and the mixture was extracted with methylene chloride (3 x 100 ml). The combined organic extracts were washed with saturated sodium chloride solution (3 x 50 ml), dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure to give 0.619 g of 1alpha,25-dihydroxyprecholecalciferol as a thick oil.
1α,25-Dihydroxycholecalciferol: A solution of 1α,25-dihydroxyprecholecalciferol [0.619 g in dioxane (30 ml)] was heated under reflux for 30 minutes under an atmosphere of argon. The reaction mixture was concentrated under reduced pressure and the residue was purified with a Waters Associates liquid chromatograph model 202 using a 8 foot * 3/8 inch Porasil A column and a 5:1 mixture of ethyl acetate-n-hexane as the eluent to give 0.474 g (80% yield based on 1α,25-diacetoxyprecholecalciferol) of pure 1α,25- dihydroxycholecalciferol. Recrystallization from methyl formate afforded 0.340 g of 1α,25-dihydroxcholecalciferol as colorless crystals, MP 113°-114°C.

brand name

Calcijex (Abbott); Rocaltrol (Roche.

Therapeutic Function

Calcium regulator

General Description

1α,25-Dihydroxyvitamin D₃, also referred as calcitriol, is a calcitrophic hormone. It is the most biologically active metabolite of vitamin D produced in proximal tubular cells in the kidney.

Biological Activity

Active metabolite of vitamin D 3 that activates the vitamin D receptor (VDR). Displays calcemic actions; stimulates intestinal and renal Ca 2+ absorption and regulates bone Ca 2+ turnover. Exhibits antitumor activity; inhibits in vivo and in vitro cell proliferation in a wide range of cells including breast, prostate, colon, skin and brain carcinomas and myeloid leukemia cells.

Biochem/physiol Actions

Biologically active form of vitamin D3 in calcium absorption and deposition. 1α,25-Dihydroxyvitamin D3 has widespread effects on cellular differentiation and proliferation, and can modulate immune responsiveness, and central nervous system function. Recent studies suggest that 1α,25-dihydroxyvitamin D3 acts as a chemopreventive agent against several malignancies including cancers of the prostate and colon and shows synergy with other anticancer compounds.

Clinical Use

Vitamin D analogue:

Promotes intestinal calcium absorption

Suppresses PTH production and release

Veterinary Drugs and Treatments

Calcitriol may be potentially beneficial in the adjunctive treatment of chronic renal disease in dogs and cats but its use is somewhat controversial, particularly the decision on how soon in the course of chronic renal insufficiency it should employed. It may also be of benefit in treating some types of dermatopathies (primary idiopathic seborrhea).

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

Metabolism

During transport in the blood at physiological concentrations, calcitriol is mostly bound to a specific vitamin D binding protein (DBP), but also, to a lesser degree, to lipoproteins and albumin. At higher blood calcitriol concentrations, DBP appears to become saturated, and increased binding to lipoproteins and albumin occurs. Calcitriol is inactivated in both the kidney and the intestine, through the formation of a number of intermediates including the formation of the 1,24,25-trihydroxy derivatives. It is excreted in the bile and faeces and is subject to enterohepatic circulation.

storage

Desiccate at -20°C