in rats: benurestat administration, 25, 50, or 100 mg per kg, caused a decrease in the urinary excretion of ammonia from rats with experimental P. mirabilis genitourinary tract infection.

Urease activity was measured with a substrate concentration of 5 mg/ml using an ammonium-sensitive electrode, and expressed as micromoles of urea hydrolyzed per minute per milligram of protein. The concentrations of benurestat producing 50% inhibition of urease was determined directly, by adding the inhibitor solution to the substrate before the enzyme, and after preincubation (5 min) of enzyme with inhibitor before addition to the reaction vessel.