Synergism between the brushite and hydroxyapatite urinary crystallization inhibitors.

The aim of this paper is to study possible synergic effects between crystallization-inhibitor molecules of low molecular weight on the hydroxyapatite and brushite crystal nucleation. Kinetic-turbidimetric measurements were performed to follow the nucleation process in synthetic urine at 37 degrees C. Only pyrophosphate + phytate mixture manifested synergic effects on the brushite nucleation, whereas the mixture pyrophosphate + citrate exhibited synergic effects only on the hydroxyapatite nucleation. It seems clear that synergic effects between the crystallization inhibitory capacity of some substances in urine can take place and as a consequence, the high crystallization inhibitory capacity of healthy urine could be assigned not only to the individual inhibitory capacity of each product but also to the synergic effects between different products.