A Comparison of Inhibitors of the Crystallization of Calcium Oxalate in Two High-Supersaturation Systems

Abstract

In recent years there have been many reports on the relative potencies of various urinary inhibitors of calcium oxalate crystallization (1-5). Most of these studies, however, have been carried out at low levels of supersaturation using either diluted urine or additives to modify the rates of crystal growth (2, 5) and/or agglomeration (1, 5) of calcium oxalate seed crystals added to the system. More recently, attempts have been made to determine the effects of various urinary constituents using a continuous crystallizer (6), a system involving crystallization at a constant composition (7) and an evaporation system (8). In this study we report on the measurement of the rates of growth and agglomeration of calcium oxalate crystals using both batch and continuous crystallizer systems. The crystals are generated in situ at high levels of supersaturation approximating to those in the urine of recurrent calcium oxalate stone formers.