Pharmacokinetics of ibuprofen following a single administration of a suspension containing enteric-coated microcapsules.

The relative bioavailability of ibuprofen (CAS 15687-27-1) was investigated following a single administration of a suspension containing enteric-coated microcapsules (A) in comparison to a rapid-release film-coated tablet (B) and a sustained-release tablet (C). The study was carried out in a three-way crossover design in 9 healthy male volunteers. Each formulation contained 800 mg ibuprofen. Plasma concentrations of ibuprofen were determined with a specific HPLC method. A mean relative bioavailability of 0.96 (B) and 1.01 (C) was determined for the test formulation. Since the corresponding 90% confidence intervals were within the recommended limits, bioequivalence for the extent of bioavailability of the test formulation can be concluded. Differences in pharmacokinetics were observed for the rate-dependent parameters. For the test formulation, the highest mean maximum plasma concentration (54.3 micrograms/ml) was measured with a corresponding tmax of 1.9 h. For the reference formulations, mean peak plasma concentrations of 45.2 micrograms/ml after 2.6 h (B) and 25.7 micrograms/ml after 5.6 h (C) were observed. Despite the enteric coating of the microcapsules, a very short lagtime of 0.03 h was determined for the suspension. For the other rapid release formulation (B), the lagtime was in a similar magnitude (0.11 h), while the absorption from the sustained-release tablet was clearly decelerated (tlag = 0.97 h). In comparison to the other rapid-release formulation (B), significant higher amounts of the drug were absorbed from the test formulation (A) within the first hour.