title: Kinetics of thiamin and thiamin phosphate esters in human blood, plasma and urine after 50 mg intravenously or orally.
abstract: The concentrations of thiamin and thiamin monophosphate and diphosphate in plasma and whole blood samples were assessed in six healthy subjects for 12 h and in urine for 24 h following an IV and PO bolus dose of 50 mg thiamin HCl. Unphosphorylated thiamin increased rapidly in plasma after IV administration and then decreased to its initial value within 12 h in all but one subject; the half-life was 96 min. Thiamin mono and -diphosphate increased moderately (56%), and decreased slowly; the half-life of diphosphate was 664 min. Within 24 h, 53% of the administered dose was recovered in the urine, indicating a restricted distribution. After oral administration, the peak thiamin concentration in plasma was reached after 53 min and the concentration then had increased to 179% of its initial value. The elimination half-life was 154 min, and only 2.5% of the given dose was recovered in the urine. The relative bioavailability of thiamin was 5.3%. A moderate amount of the administered thiamin was stored in blood. Other body tissues must play an important part, therefore, in the distribution of thiamin.
authors.affiliation: Medical Department, Aker University Hospital, Norway.
authors.forename: C M
authors.initials: CM
authors.lastname: Tallaksen
authors.forename: A
authors.initials: A
authors.lastname: Sande
authors.forename: T
authors.initials: T
authors.lastname: Bøhmer
authors.forename: H
authors.initials: H
authors.lastname: Bell
authors.forename: J
authors.initials: J
authors.lastname: Karlsen
mesh_terms: D000284:Administration, Oral; D000328:Adult; D006207:Half-Life; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D013831:Thiamine / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D013833:Thiamine Monophosphate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013835:Thiamine Pyrophosphate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D013833:Thiamine Monophosphate; D013835:Thiamine Pyrophosphate; D013831:Thiamine