Intra-articular absorption and distribution of ketoprofen after topical plaster application and oral intake in 100 patients undergoing knee arthroscopy

Objective. The primary objective of this study was to assess the kinetics o f ketoprofen in synovial fluid and intra-articular tissues in relation to p lasma. The secondary objective was to study whether intra-articular tissues act as reservoirs. Methods. The ketoprofen concentration was analysed in plasma, synovial flui d and intraarticular tissues after single application of a 30 mg plaster (n = 40), multiple applications for 5 days (n = 30) or oral intake of 50 mg ( n = 30) in patients undergoing knee arthroscopy. Results. Median CMax values after topical application were 12.8 ng/ml in sy novial fluid, 56.7 ng/g in synovial tissue, 349.3 ng/g in meniscus and 568. 9 ng/g in cartilage. Conclusion. Topical applications of ketoprofen allow the attainment of high intra-articular tissue concentrations.