Dissolution kinetics of uric acid calculi.

Dissolution of uric acid calculi was studied in vitro. Calculated rate constants were then applied to an in vivo situation. The time required for complete dissolution of a uric acid calculus in a patient on oral alkali therapy can be estimated. Sodium bicarbonate, acetylcysteine, [tris(hydroxymethyl)aminomethane] and [tris(hydroxymethyl)aminomethane]-E were tested for relative effectiveness in dissolving uric acid calculi in vitro. In patients who require irrigation for dissolution of uric acid calculi [tris(hydroxymethyl)-aminomethane] is the preferred agent.