Anion exchange and t.l.c. were used to collect the polar drug metabolites present in urine of dogs treated orally with [14C]bunolol. 2. A new metabolite, 5-hydroxytetralone, was isolated, purified, and identified by u.v.,i.r. and mass spectroscopy. 3. 5-Hydroxytetralone represented 1.7% dose excreted in urine collected for 24 h after bunolol administration. 4. Properties of the metabolite are discussed in relation to the question of whether 5-hydroxytetralone was excreted as a conjugate.
