Forti-D Mechanism of Action

Soft gelatin cap: 5,000 IU: Pharmacotherapy group: Vitamin D and analogues.
Pharmacology: Pharmacodynamics: Absorption: Cholecalciferol is easily absorbed in the small intestine.
In its biologically active form, Cholecalciferol stimulates calcium absorption through the intestines, assimilate calcium into the osteoid and release of calcium from bone tissue. In the small intestine, Cholecalciferol in its active form triggers rapid and delayed absorption of calcium. Cholecalciferol also stimulates passive and active transport of phosphate. In the kidney, Cholecalciferol in its active form inhibits the excretion of calcium and phosphate by promoting tubular resorption. The production of parathyroid hormone (PTH) in the parathyroid is directly inhibited by the biologically active form of Cholecalciferol.
In addition, PTH secretion is also inhibited by increased calcium absorption in small intestine under the influence of the biologically active Cholecalciferol.
Elimination: Cholecalciferol and other forms of vitamin D are excreted in the feces and urine.
Pharmacokinetics: The pharmacokinetic of Cholecalciferol is well known. Cholecalciferol is almost completely absorbed from gastrointestinal tract with the presence of dietary fats and bile acids, Cholecalciferol is stored in fat cells and the half-life is about 50 days.
Cholecalciferol is metabolized by microsomal hydroxylase to be 25-hydrocholecalciferol (25(OH)D3, calcidiol) which is the main storage form of vitamin D3 which is further hydroxylated in the kidney to be the active metabolite 1,25 dihydroxycholecalciferol (calcitriol). These metabolites circulate in the blood and are bound to a specific α-globulin.
After a single oral dose of cholecalciferol, the maximum serum concentrations of the primary storage form are reached after approximately 7 days. 25-hydroxycholecalciferol (25(OH)D3) is then slowly eliminated with an apparent half-life in serum of about 50 days. Cholecalciferol and its metabolites are excreted mainly in the bile and feces. After high doses of Cholecalciferol, the serum concentration of 25(OH)D3 may increase for several months. Overdose-induced hypercalcemia may persist for several weeks (see "OVERDOSAGE").