Trace Metal-Citric Acid Complexes as Inhibitors of Calcification and Crystal Growth: II. Effects of Fe(III), Cr)III) and Al(III) Complexes on Calcium Oxalate Crystal Growth

Abstract

The high molecular weight Fe (III)-citric acid complex, formed at low ratios of citrate:iron in solution, has been shown to be an effective inhibitor of calcium oxalate crystal growth. This appears to be a specific reaction, since 2 other similar metal ions, Al(III) and Cr(III), exhibit no synergism with citric acid in this system. Because the low molecular weight Fe (III)-citric acid complex, formed at high ratios of citratedron, inhibits calcium phosphate precipitation but has no effect on calcium oxalate, the Fe (III)-citric acid system might have a selective biologic role in regulating the growth of calcium-containing urinary calculi in vivo.