High-performance liquid chromatographic determination with amperometric detection of piroxicam in human plasma and tissues

After repeated topical application of a piroxicam eel preparation to the kn ee, piroxicam was quantified in plasma, subcutaneous tissue, synovial capsu le and synovial fluid, using specimens obtained during knee surgery. Electr ochemical detection was used and the limit of quantification (LOQ) was 0.72 ng/ml in plasma at a signal-to-noise ratio of 10:1. The chromatographic me thod was optimised to determine piroxicam in all four matrices, and the ana lyte was quantified using a calibration line constructed from plasma calibr ation standards. Levels in subcutaneous tissue, synovial capsule and synovi al fluid were compared to plasma steady-state levels and expressed as a rat io, in order to ascertain bioavailability. (C) 1999 Published by Elsevier S cience B.V. All rights reserved.