Gastrointestinal transit of amoxicillin modified-release tablets and a placebo tablet including pharmacokinetic assessments of amoxicillin.

Background: We have investigated the gastrointestinal transit time of, the influence of food intake on, the disintegration of, and the pharmacokinetics of amoxicillin in a modified-release form.
Methods: Radiolabelled modified-release tablets of amoxicillin and placebo tablets were administered, in an open three-way, randomized, crossover design, as single doses during omeprazole treatment, to six male healthy subjects during fasting and non-fasting conditions. Radioscintigraphic images and plasma samples were obtained.
Results: The estimated mean (and range) gastric emptying time of the modified-release tablet after drug administration was 0.3 h (0.1-1.0 h) during fasting conditions, 4.3 h (1.7-5.0 h) after a light breakfast, and 4.9 h (1.9-18.0 h) after a heavy breakfast. The small-intestinal transit time during fasting conditions was 4.7 h (2.9-6.9 h) and was not significantly changed after light or heavy breakfast intake. The relative bioavailability of the modified-release tablet was 55%, compared with a commercially available amoxicillin immediate-release tablet.
Conclusion: The modified-release tablet of amoxicillin administered postprandially apparently increases the amoxicillin release time in the stomach. The relevance of its use for anti-H. pylori treatment can be questioned.