[In vitro and first in vivo experiments for the dissolution of calcium-containing urinary calculi (author's transl)]

There are numerous reports dealing with the significantly reduced citrate secretion in (recurrent) tone formers. The critical values of the Ca/citrate ratio in the nocturnal urine of (oxalate) stone formers has also been reported, emphasizing the need of medicaments being capable to increase the citrate secretion and to raise the basal citrate level of the nocturnal urine in these patients. In our in vitro experiments, we tested quantitatively the inhibitory activity of some new substances on crystal growth. In Wistar rats we measured the Ca2+-binding capacity as well as the citrate and oxalate excretion before and after oral application of a great number of new compounds. Some of them were highly efficacious in the reduction of the Ca-oxalate activity product, as can be derived from the increased Ca2+-binding capacity and/or the decreased oxalate secretion in urine.