Concentrations of indomethacin and its metabolite desmethylindomethacin in plasma and urine after repeated indomethacin topical application to Thoroughbreds.

Pharmacokinetic data were acquired for repeated topical administration of 1% indomethacin cream to Thoroughbreds. Hydrolysing urine samples with hydrochloric acid was effective for the analysis of indomethacin and its metabolite, and indomethacin may be an excellent marker analyte for doping tests. The estimated withdrawal time based on the limit of detection was 342 h.