Tolerability and serum levels of benoxaprofen in healthy volunteers.
Tolerability, serum levels and urinary excretion of benoxaprofen (B) in therapeutic doses of 400 or 600 mg as a capsule were studied in 22 healthy volunteers after single or multiple doses. B was determined by a HPLC procedure. Apart from a skin reaction in one patient, no major problems were encountered by patients. Mean serum peak values after 400 and 600 mg were 49.84 and 94.54 micrograms/ml respectively. Mean time to peak was 5.6 hours and mean half-life ranged between 45.38 (400 mg regimen) and 63.48 hours (600 mg regimen). Urinary excretion was only a fraction of the doses ingested: 14.39% after a single dose; 35.5% after multiple doses. This may depend on other pathways of elimination of the drug because steady state is reached according to half-life.