Pharmacotherapeutic Group: Vitamins, other plain vitamin preparations. ATC code: A11HA05.
Pharmacology: Pharmacodynamics: Biotin is traditionally considered to be a vitamin B substance. It is an essential coenzyme in fat metabolism and in other carboxylation reactions. Biotin deficiency may result in the urinary excretion of organic acids and changes in skin and hair.
Deficiency of biotin is very unlikely in man because of its widespread distribution in food. Egg-yolk and offal are especially good sources. Biotin deficiency has been reported however during long-term parenteral nutrition and in patients with biotinidase deficiency, an inherited metabolic disorder. For dosage in biotinidase or isolated carboxylase deficiency see "Dosage & Administration". A combination of biotin and chromium tripicolinate has been promoted as an adjunct for the management of diabetes mellitus. Biotin combines with avidin, a glycoprotein present in raw eggwhite, to form an inactive compound.
Pharmacokinetics: Biotin enters the human organism from food and it is also synthesized by human intestine microflora. In organism Biotin is rapidly absorbed in small intestine by a passive diffusion, and after that it passes through the portal system into liver and then into systemic circulation. Biotin binding with plasma proteins is approximately 80%.
Concentration of free or weakly bound Biotin in blood as a rule is from 200 to 1200 mkg/l. Biotin passes through the hematoencephalic and placental barriers. In human it is metabolized to different metabolites. Biotin is excreted with urine (from 6 to 50 µg per day) and with feces in unchanged form (approximately 50%) and also as biologically inert metabolite. Half-life period depends on the amount of given dose and it is about 26 hours after intake of 100 µg per kg of body weight.