PHARMACOKINETICS AND RELATIVE BIOAVAILABILITY AFTER SINGLE-DOSE ADMINISTRATION OF 25 MG KETOPROFEN SOLUTION AS COMPARED TO TABLETS

The relative bioavailability of ketoprofen from a liquid formulation a s compared to a tablet annulation as reference after single oral dose administration was investigated in 16 healthy male subjects. The subje cts received in a randomized, crossover design during one study period of 5 days 25 mg of ketoprofen as tablet or liquid formulation adminis tered as single dose with a washout interval of 48 h. The plasma conce ntrations of S(+)- and R(-)-ketoprofen were determined before and up t o 24 h post-administration. S(+)- and R(-)-ketoprofen in the collected plasma samples was determined using an internally standardized valida ted HPLC method. Regarding the geometric mean concentration-time cours es there were no relevant differences between the two ketoprofen enant iomers for both formulations. Remarkable differences in the shape of c oncentration-time courses between the two formulations were found with higher C-max (by about 70%) and earlier t(max) (by 15 min) values for the ketoprofen solution. The treatments were widely equivalent with r egard to AUC. The quotients of geometric means as well as 90% confiden ce intervals for AUC of R(-)-ketoprofen were 95.72% (92.55-99.00%) and for S(+)-ketoprofen 94.23% (89.91-98.76%). The administration of the ketoprofen solution resulted earlier in higher concentrations (by abou t 70%)Sor both enantiomers, whereas the extent of absorption expressed by A UC was nearly the same (about 95%) as compared to the equimolar tablet formulation. The differences between the two formulations for C -max,C-norm and t(max) were statistically significant.