title: Bioavailability of amoxicillin and clavulanic acid from extended release tablets depends on intragastric tablet deposition and gastric emptying.
abstract: The rate and extent of amoxicillin and clavulanic acid absorption from pharmacokinetically enhanced extended release (ER) tablets is strongly influenced by the intake conditions. In order to investigate the cause of the food effects, a pharmacokinetic study with simultaneous imaging of the in vivo behaviour of the ER tablets by magnetic marker monitoring (MMM) was performed. Under fasting conditions the amoxicillin AUC (1854+/-280microg min ml(-1)) was significantly lower than after intake at the beginning of the breakfast (2452+/-354microg min ml(-1)) or after the breakfast (2605+/-446microg min ml(-1)). In contrast, clavulanic acid AUC was well comparable after tablet intake under fasting conditions and intake at the beginning of a breakfast (191+/-46 and 189+/-44microg min ml(-1), respectively) but significantly lower following a breakfast (126+/-71microg min ml(-1)). The localization data showed that the reduced bioavailability of amoxicillin under fasting conditions is due to early gastric emptying in combination with poor absorption from deeper parts of the small intestine. Prolonged gastric residence of clavulanic acid caused by intragastric tablet deposition in the proximal stomach was identified as the reason for the decreased bioavailability of clavulanic acid after tablet intake following the meal.
authors.affiliation: Department of Biopharmaceutics, University of Greifswald, Greifswald, Germany. werner.weitschies@uni-greifswald.de
authors.forename: W
authors.initials: W
authors.lastname: Weitschies
authors.forename: C
authors.initials: C
authors.lastname: Friedrich
authors.forename: R S
authors.initials: RS
authors.lastname: Wedemeyer
authors.forename: M
authors.initials: M
authors.lastname: Schmidtmann
authors.forename: O
authors.initials: O
authors.lastname: Kosch
authors.forename: M
authors.initials: M
authors.lastname: Kinzig
authors.forename: L
authors.initials: L
authors.lastname: Trahms
authors.forename: F
authors.initials: F
authors.lastname: Sörgel
authors.forename: W
authors.initials: W
authors.lastname: Siegmund
authors.forename: S
authors.initials: S
authors.lastname: Horkovics-Kovats
authors.forename: F
authors.initials: F
authors.lastname: Schwarz
authors.forename: J
authors.initials: J
authors.lastname: Raneburger
authors.forename: H
authors.initials: H
authors.lastname: Mönnikes
mesh_terms: D000328:Adult; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D001682:Biological Availability; D003692:Delayed-Action Preparations; D005260:Female; D005746:Gastric Emptying; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D008280:Magnetics; D008297:Male; D012995:Solubility; D013607:Tablets
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D013607:Tablets; D019980:Amoxicillin-Potassium Clavulanate Combination