Disposition and metabolism of (14C) bermoprofen in rats after single administration.

Abstract

Disposition and metabolism of [14C]bermoprofen were studied in rats after oral administration mainly at the dose of 3 mg/kg. It was suggested that bermoprofen was absorbed from the whole region of small intestine. The extent of gastrointestinal absorption was estimated to be virtually complete based on the ratio of urinary excretion of radioactivity after oral/intravenous administration. Blood level reached the maximum of about 2.0 μg eq./ml at 30 min after oral administration and decreased with the half life of 2.6 hr. Maximum concentrations in most tissues were reached at 1 hr after oral administration. The kidney had the highest level of radioactivity, which was about 2.8 times higher than that in the plasma while the liver, was 0.69 of plasma. Other tissue levels were <1/3 of plasma level. Drug concentration in the central nervous systemwas the lowest. Fetal and milk levels were 0.07 and 0.18 of plasma level in pregnant and lactating rats, respectively. The extent bermoprofen of binding to serum proteins was 99.6%. Approximately 70 % and 30 % of radioactivity were excreted in urine and feces, respectively, after oral or intravenous administration. About 46 % was excreted in the bile of rats with biliary fistula, of which about 46 % were re-absorbed when the radioactive bile was abministered to another rat. Bermoprofen was known to be metabolized mainly by oxidation of methyl group, reduction of carbonyl group and conjugation at propionyl group, and the first biotransformation pathway was found to be predominant in rats.