No abstract

The effect of tetrasodium pyrophosphate on struvite nucleation and growth in the context of infectious urinary stone formation is studied. The crystallization processes occurred in artificial urine, while urease activity was simulated in a chemical way. The spectrophotometric results show that the presence of tetrasodium pyrophosphate causes a delay of struvite nucleation and decrease in growth efficiency. These results are explained on the basis of theoretical chemical speciation analysis of different complexes formed in artificial urine. The obtained results clearly show that the formation of the MgP 2 O 7 2− complex plays the most important role in inhibition of struvite nucleation. It has been also found that tetrasodium pyrophosphate causes changes in struvite morphology and habit.

The influence of (−)-epicatechin, a component of green tea, on the nucleation and growth of struvite crystals, the main component of infectious urinary stones, is studied. The struvite crystallization process was performed in the solution of artificial urine, and the activity of urease−bacterial enzyme was simulated in a chemical way. The effect of the tested substance on the crystallization processes was monitored by spectrophotometric measurements and microscopic observations. The results obtained show that, in the presence of (−)-epicatechin, struvite nucleation occurs faster when compared with the control test. This means that its nucleation is shifted toward lower pH values. It has been also found that the presence of the tested substance can lead to an increase in the mass of struvite formed in artificial urine. The experimental results are explained on the basis of theoretical chemical speciation analysis of chemical complexes formed in artificial urine. This chemical speciation analysis demonstrates that the observed effects are caused by the influence of (−)-epicatechin on the formation of mainly the MgCit– complex and also the MgHCit and MgC2O4 complexes.