title: Vitamin C pharmacokinetics of plain and slow release formulations in smokers.
abstract: OBJECTIVE
  Combination of the antioxidants ascorbic acid in slow release formulation and alpha-tocopherol can retard the progression of atherosclerosis. In order to determine if differences in formulation could explain some of the different results in the intervention trials we determined selected pharmacokinetics for two different formulations of ascorbic acid together with alpha-tocopherol.
  
  
  METHODS
  Single-blinded, randomised, placebo-controlled intervention study with 48 healthy men, aged 20-65 years, smoking > or = 5 cigarettes/day. Subjects received 250 mg plain release ascorbic acid and 91 mg plain release d-alpha-tocopheryl acetate, 250 mg slow release ascorbic acid and 91 mg plain release d-alpha-tocopheryl acetate or placebo twice daily for 4 weeks. A series of blood samples were collected after administration of the first dose and repeated after 4 weeks of supplementation.
  
  
  RESULTS
  The fluctuation of ascorbic acid plasma concentrations decreased significantly (P = 0.003) after 4 weeks supplementation in the slow versus the plain release group.
  
  
  CONCLUSIONS
  This study shows that there were pharmacokinetic differences between plain and slow release formulations of ascorbic acid. However, these effects are small and unlikely to be of significant clinical importance.
authors.affiliation: Department of Clinical Pharmacology Q 7642, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Viscovich
authors.forename: Jens
authors.initials: J
authors.lastname: Lykkesfeldt
authors.forename: Henrik E
authors.initials: HE
authors.lastname: Poulsen
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001161:Arteriosclerosis / Q000517:prevention & control; D001205:Ascorbic Acid / Q000097:blood / Q000493:pharmacokinetics*; D003692:Delayed-Action Preparations; D018450:Disease Progression; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D012907:Smoking / Q000097:blood / Q000378:metabolism*; D024502:alpha-Tocopherol / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000975:Antioxidants; D003692:Delayed-Action Preparations; D024502:alpha-Tocopherol; D001205:Ascorbic Acid