title: Influence of simulated weightlessness on the oral pharmacokinetics of acetaminophen as a gastric emptying probe in man: a plasma and a saliva study.
abstract: This study evaluated the effect of simulated weightlessness on gastric emptying, using acetaminophen as a probe and -6 degrees head-down bed rest to simulate zero gravity. Eighteen volunteers were given 1 g of acetaminophen orally before the bed rest and at days 1, 18, and 80. Cmax, tmax, AUC0- infinity, AUC0-t, and t1/2 were calculated for plasma and saliva. The plasma Cmax showed a significant increase (10.43 microg/mL [day 1] to 14.74 microg/mL [day 80]), while tmax significantly decreased (1.41 h [day 1] to 0.91 h [day 80]). Similar results were obtained with saliva, and there were significant increases in the AUCs. The good correlation between the plasma and saliva data suggests that saliva sampling can be valid for acetaminophen pharmacokinetics. The changes in Cmax and tmax indicated more rapid drug absorption, which could have been as a result of faster gastric emptying or an increased blood flow to the intestine.
authors.affiliation: Hôpital Rangueil-Larrey, Toulouse, France.
authors.forename: Peggy
authors.initials: P
authors.lastname: Gandia
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Bareille
authors.forename: Sylvie
authors.initials: S
authors.lastname: Saivin
authors.forename: Anne Pavy
authors.initials: AP
authors.lastname: Le-Traon
authors.forename: Michel
authors.initials: M
authors.lastname: Lavit
authors.forename: Antonio
authors.initials: A
authors.lastname: Guell
authors.forename: Georges
authors.initials: G
authors.lastname: Houin
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage* / Q000097:blood*; D000284:Administration, Oral; D000328:Adult; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology*; D018475:Head-Down Tilt / Q000502:physiology; D006801:Humans; D008297:Male; D012463:Saliva / Q000187:drug effects / Q000378:metabolism*; D018709:Statistics, Nonparametric; D014893:Weightlessness
chemical_list: D000082:Acetaminophen