PHARMACOKINETICS OF IBUPROFEN FOLLOWING A SINGLE ADMINISTRATION OF A SUSPENSION CONTAINING ENTERIC-COATED MICROCAPSULES

The relative bioavailability of ibuprofen (CAS 15687-27-1) was investi gated following a single administration of a suspension containing ent eric-coated microcapsules (A) in comparison to a rapid-release film-co ated tablet (B) and a sustained-release tablet (C). The study was carr ied 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 wi thin the recommended limits, bioequivalence for the extent of bioavail ability of the test formulation can be concluded. Differences in pharm acokinetics were observed for the rate-dependent parameters. For the t est formulation, the highest mean maximum plasma concentration (54.3 m u g/ml) was measured with a corresponding t(max) of 1.9 h. For the ref erence formulations, mean peak plasma concentrations of 45.2 mu g/ml a fter 2.6 h (B) and 25.7 mu g/ml after 5.6 h (C) were observed. Despite the enteric coating of the microcapsules, a very short lagtime of 0.0 3 h was determined for the suspension. For the other rapid release for mation (B), the lagtime was in a similar magnitude (0.11 h), while the absorption from the sustained-release) tablet was clearly decelerated (t(lag) = 0.97 h). In comparison to the other rapid-release formulati on (B), significant higher amounts of the drug were absorbed from the test formulation (A) within the first hour.