Surf Wiki
Save to docs
general/secosteroids

From Surf Wiki (app.surf) — the open knowledge base

Alfacalcidol

Alfacalcidol

Alfacalcidol (or 1-hydroxycholecalciferol) is an analogue of vitamin D used for supplementation in humans and as a poultry feed additive.

Alfacalcidol has a weaker impact on calcium metabolism and parathyroid hormone levels than calcitriol; but significant effects on the immune system, including regulatory T cells. It is considered to be a more useful form of vitamin D supplementation, mostly due to its much longer half-life and lower kidney load. It is the most commonly prescribed vitamin D metabolite for patients with end stage renal disease, given that impaired renal function alters the ability to carry out the second hydroxylation step required for the formation of the physiologically active form of vitamin D, 1,25-dihydroxyvitamin D3. Alfacalcidol is an active vitamin D3 metabolite, and therefore does not require the second hydroxylation step in the kidney.

Mechanism of action

Action of alfacalcidol in vitamin D<sub>3</sub> metabolism

Alfacalcidol is a prodrug that is rapidly metabolized in the liver to the active form, calcitriol. As it is already 1α-hydroxylated, it does not require activation in the kidney as cholecalciferol does. After calcitriol binds to its intracellular receptor (vitamin D receptor, VDR), the synthesis of a calcium ion-binding protein increases. The compound enhances intestinal absorption of calcium and phosphate, regulates bone mineralization, and promotes calcium reabsorption in the renal tubules.

Alfacalcidol prevents deficiency symptoms associated with impaired physiological 1α-hydroxylation of cholecalciferol or calcifediol in the kidneys, particularly in cases of chronic renal insufficiency. Alfacalcidol is not naturally present in the human body and is rapidly converted into calcitriol in the liver.

Synthesis

The multi-step synthesis of alfacalcidol is illustrated in the following reaction sequence:

zentriert

Properties

Alfacalcidol is practically insoluble in water, slightly soluble in 96% ethanol, and soluble in fatty oils. It is sensitive to air, heat, and light. In solution, a reversible isomerization to pre-alfacalcidol occurs, depending on temperature and duration. Both compounds are biologically active.

History

Alfacalcidol was patented in 1971 and approved for medical use in 1978.

Trade names

Pharmaceutical trade names include AlphaD and One-Alpha.

Other animals

Used as a poultry feed additive, it prevents tibial dyschondroplasia and increases phytate bioavailability.

References

References

  1. (9 November 2017). "One-Alpha Capsules - Summary of Product Characteristics (SmPC)".
  2. (11 February 2021). "List of nationally authorised medicinal products".
  3. (May 2009). "Biological effects of various regimes of 25-hydroxyvitamin D3 (calcidiol) administration on bone mineral metabolism in postmenopausal women". Clinical Cases in Mineral and Bone Metabolism.
  4. (2008). "Oral calcitriol versus oral alfacalcidol for the treatment of secondary hyperparathyroidism in patients receiving hemodialysis: a randomized, crossover trial". The Canadian Journal of Clinical Pharmacology.
  5. (January 2011). "Alfacalcidol treatment restores derailed immune-regulation in patients with undifferentiated connective tissue disease". Autoimmunity Reviews.
  6. (March 2006). "Superiority of alfacalcidol compared to vitamin D plus calcium in lumbar bone mineral density in postmenopausal osteoporosis". Rheumatology International.
  7. (December 2001). "Alfacalcidol in the therapy of renal bone disease". International Journal of Clinical Pharmacology and Therapeutics.
  8. G. Geisslinger, S. Menzel, T. Gundermann, B. Hinz, P. Roth (Hrsg.): Mutschler Arzneimittelwirkungen. 11. Auflage. Wissenschaftliche Verlagsgesellschaft, Stuttgart 2020, S. 1148 ff.
  9. {{RömppOnline
  10. [[Axel Kleemann]], J. Engel, B. Kutscher, D. Reichert. (2014-05-14). "Pharmaceutical Substances, 5th Edition: Syntheses, Patents and Applications of the most relevant APIs". Georg Thieme Verlag.
  11. Monographie „Alfacalcidol“, European Pharmacopoeia 10th Edition (Ph. Eur. 10.0), EDQM Council of Europe, 2019.
  12. (2006). "Analogue-based Drug Discovery". John Wiley & Sons.
  13. "Vitamin Derivatives".
Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

secosteroids vitamin-d methylidenes
Want to explore this topic further?

Ask Mako anything about Alfacalcidol — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report