Folic acid is rapidly absorbed in the jejunum, subject to reduction and methylation to 5-methyl-tetrahydrofolate. The maximum concentration in plasma is observed after 30-60 minutes.
Intensively binds to plasma proteins.Penetrates through the blood-brain barrier, into the placenta and breast milk. It is excreted by the kidneys mainly in the form of metabolites. Vitamin B12 can be absorbed after its interaction in the stomach with the internal factor of the Castle, the glycoprotein, which is secreted by the parietal cells of the stomach. The maximum concentration in plasma is observed after 8-12 hours. As with folic acid, the vitamin B12 is subject to significant enteric-liver recirculation.
The average half-life of the vitamin B12 is about 6 days. Part of the dose administered is excreted by the kidneys within the first 8 hours, although most of it is excreted with bile. 25% is excreted through the intestine. In addition, the vitamin B12 penetrates the placenta and is present in breast milk.
Vitamin B12 it binds to a considerable extent with plasma proteins, the excess accumulates in the liver.
Iodine has a good absorption. It is believed that the coefficient of intestinal absorption of iodine after the intake of water-soluble iodine salts (for example, potassium iodide) is 100%. The mechanism of intestinal absorption of iodine is not known.
After completion of the absorption process iodine quickly spreads through the intercellular fluid. Iodine penetrates the placental barrier and is present in breast milk. Iodine is transported to other tissues (except for the thyroid gland tissue): the milk / salivary glands and the intestinal mucosa.
The main part of iodine is excreted by the kidneys and a small amount with saliva, milk, sweat, bile and through the intestine.