البلد: أستراليا
اللغة: الإنجليزية
المصدر: Department of Health (Therapeutic Goods Administration)
calcitriol
Arrow Pharma Pty Ltd
Calcitriol
Registered
KOSTEO – Product Information Page 1 of 11 Kosteo PRODUCT INFORMATION NAME OF THE MEDICINE Calcitriol CAS 32222-06-3 The chemical name for calcitriol is 1,25-dihydroxycholecalciferol, the molecular formula is C 27 H 44 O 3 . Calcitriol has a molecular weight of 416.65. DESCRIPTION Calcitriol is a white, crystalline compound, which occurs naturally in humans. It is soluble in organic solvents but practically insoluble in water. Kosteo is available as soft gelatin capsules containing 0.25 micrograms of calcitriol. Each capsule also contains butylated hydroxyanisole, butylated hydroxytoluene, medium chain triglyceride, gelatin, glycerol, sorbitol (70 percent, non-crystallising), iron oxide red CI77491 and iron oxide yellow CI77492. PHARMACOLOGY PHARMACODYNAMICS Calcitriol is the most important active metabolite of vitamin D 3 . It is normally formed in the kidney from its precursor 25-hydroxycholecalciferol (25-HCC). Physiological daily production is normally 0.5 - 1.0 µ g and is somewhat higher during periods of increased bone synthesis (eg growth or pregnancy). The natural supply of vitamin D in humans depends mainly on exposure to ultraviolet rays of the sun for conversion of 7-dehydrocholesterol in the skin to vitamin D 3 (cholecalciferol). Vitamin D 3 must be metabolically activated in the liver and the kidney before it is fully active as a regulator of calcium and phosphorus metabolism at target tissues. The initial transformation of vitamin D 3 is catalysed by a vitamin D 3 -25-hydroxylase enzyme (25-OHase) present in the liver, and the product of this reaction is 25-hydroxyvitamin D 3 [25-(OH) D 3 ]. Hydroxylation of 25-(OH) D 3 occurs in the KOSTEO – Product Information Page 2 of 11 mitochondria of kidney tissue, activated by the renal 25-hydroxyvitamin D 3 -1 alpha-hydroxylase (alpha-OHase), to produce 1,25-(OH)2 D 3 (calcitriol), the active form of vitamin D 3 . Calcitriol binds to an intracellular receptor, a member of the steroid receptor superfamily. The calcitriol-receptor complex interacts with s اقرأ الوثيقة كاملة