title: Effect of structured dietary fiber on bioavailability of amoxicillin.
abstract: The effect of structured dietary fiber on the bioavailability of amoxicillin (AMX) was evaluated. Ten healthy volunteers ingested one of two isocaloric, isonitrogenous diets providing 7.8 gm/day (diet I) and 36.2 gm/day (diet II) of structured fiber for 3 days. Then they ingested one tablet (500 mg) AMX after breakfast. The other diet was administered for an additional 3 days and the study was repeated. Plasma and urinary AMX concentrations were measured at 9 and 24 hours, respectively, by a microbiologic technique. An open one-compartment model was used for pharmacokinetic analysis. AMX was absorbed more slowly when ingested with diet I than with diet II: the absorption rate constant was 1.04 +/- 0.37 and 1.75 +/- 0.75 (P less than 0.05); lag time for absorption was 0.34 +/- 0.13 hours and 0.29 +/- 0.11 hours (P less than 0.05). The first-order rate constant and elimination half-life were similar. Bioavailability was higher with diet I: the AUC was 12.17 +/- 3.04 vs. 9.65 +/- 2.64 micrograms/ml/hr with diet II (P less than 0.05). A higher content of dietary fiber increased AMX absorption rate and decreased the amount of drug absorbed.
mesh_terms: D000042:Absorption; D000328:Adult; D000658:Amoxicillin / Q000378:metabolism*; D001682:Biological Availability; D004043:Dietary Fiber / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008297:Male
chemical_list: D004043:Dietary Fiber; D000658:Amoxicillin