Distribution of azapropazone and its principal 8-hydroxy-metabolite in plasma, urine and gastrointestinal mucosa determined by HPLC.

Methods are described for the HPLC determination of azapropazone and its 8-hydroxyl metabolite in plasma, urine and gastrointestinal mucosae after purification of samples on reverse-phase mini columns. Plasma levels of the drug in gouty patients receiving 900-2400 mg daily were relatively constant after 5 days, though overall the values were higher than after a single dose. Gastric absorption of azapropazone in rats is relatively rapid suggesting that the low gastric irritancy is probably due to its weak inhibitory effects on prostaglandin and mucus synthesis rather than slow gastric absorption.