Development of assays and assessment of oral bioavailability of the NSAIDs ketoprofen, carprofen and flunixin in sheep

Summary

​This report details the analytical component of MLA Project B.AWW.0230 – Development of assays and assessment of oral bioavailability of the NSAIDs ketoprofen, carprofen and flunixin, contracted to Pia Pharma Pty Ltd through the CSIRO Pastoral Research Lab Chiswick, Armidale, NSW.  The objective of the analytical component was to develop analytical methodology to facilitate determination of concentrations of ketoprofen, carprofen and flunixin in plasma samples collected from test subjects following administration of investigative veterinary formulations containing the non-steroidal agents.
A sensitive, selective analytical method for the simultaneous determination of ketoprofen, carprofen, flunixin and metabolite 5-hydroxyflunixin in ovine plasma was developed and validated.  This was achieved through a combination of an efficient extraction and sample clean up procedure using a mixed mode (C8 + Anion Exchange) Solid Phase Extraction sorbent; use of deuterated equivalents as internal standards; effective chromatographic separation and peak shape using Ultra High Pressure Liquid Chromatography; and negative electrospray ionisation and tandem mass spectrometry.