An open, randomized study of ketoprofen in patients in surgery for Achilles or patellar tendinopathy

OBJECTIVE: To assess the concentration of ketoprofen, after topical plaster application, in various tissues in relation to plasma levels in 60 patients undergoing surgery for Achilles or patellar tendinopathy; and to analyze whether tissues act as a reservoir of ketoprofen, by evaluating tissue concentrations in relation to plasma concentration at various time points after removal of the plaster. No attempt was made to study the clinical effect of treatment per se. METHODS: In random order to patients applied 30 mg plasters once daily for 5 consecutive days (n = 30), or took a single oral dose 50 mg (n = 30) before surgery. Tissue samples of skin, subcutaneous fat, tendon sheath, and tendon, and plasma were collected intraoperatively at 0, 6 and 14 hours after removal of the 5th plaster, and at 2, 6, and 14 hours after oral intake. Ketoprofen concentration was determined by a validated GC/MS method. The low limit of quantification was 0.5 ng/ml plasma and 0.5 ng/50 mg tissues. RESULTS: High concentrations of ketoprofen were observed in fat, tendon sheath, and tendon after topical applications, whereas plasma levels of ketoprofen were low. CONCLUSION: Ketoprofen attains high concentrations in subcutaneous tissues after multiple topical applications. Subcutaneous tissues appear to act as a reservoir of ketoprofen.