Absorption kinetics and model characteristics of orally administered pirprofen.

Pirprofen kinetics can be described by a linear two-compartment model. Absorption kinetics and model parameters were determined by the incremental method from 48 pirprofen plasma concentration-time profiles obtained after administration of single oral pirprofen doses. Statistical comparison of the results gave information on the influence of formulation, dose, and food on pirprofen absorption. The rate of absorption decreased significantly when pirprofen was administered as a capsule in comparison with a solution. The dose (200 mg compared with 100 mg) had no marked influence on the absorption rate. Food delayed absorption. Pirprofen model parameters, estimated as the median values of the results obtained from the 48 sets of data, permitted the plasma kinetics of the drug after single and repeated doses to be predicted.