Metabolites and analogs of 2-ethyl-2,3-dihydro-5-benzofuranacetic acid (furofenac): chemical and pharmacological properties.

The in vivo metabolism of 2-ethyl-2,3-dihydro-5-benzofuranacetic acid (furofenac), a new drug, was studied in rats, dogs, and humans. The drug has antiplatelet-aggregation activity and anti-inflammatory activity combined with low ulcerogenic power. Hydroxylated derivatives and analogous compounds were prepared, and their syntheses and chemical characteristics are described. TLC. GLC, high-pressure liquid chromatography, and GLC--mass spectrometry were applied to urine extracts, and authentic synthetic specimens were used for comparison. The products identified in human and dog urine were mainly conjugation compounds of the drug, while the products in rat urine were hydroxylated derivatives. Some pharmacological characteristics of the metabolites are discussed.