Effects of Various Inhibitors on the Nucleation of Calcium Oxalate in Synthetic Urine

Abstract

A new synthetic urine was adopted in this work to study the nucleation kinetics of calcium oxalate using a batch crystallizer for various supersaturations at 37 °C. In the studied new synthetic urine, three additional components (urea, uric acid and creatinine) within the normal physiological ranges were added to the commonly-used synthetic urine to simulate human urine more closely. The interfacial energy for the nucleation of calcium oxalate was determined based on classical nucleation theory using the turbidity induction time measurements. The effects of various inhibitors, including magnesium, citrate, hydroxycitrate, chondroitin sulfate, and phytate, on the nucleation of calcium oxalate were investigated in detail. Scanning electron microscopy was used to examine the influences of these inhibitors on the preferential nucleation of the different hydrates of calcium oxalate crystals.

Suppressing Barium Sulfate Crystallization with Hydroxycitrate: A Dual Nucleation and Growth Inhibitor

“…Crystal growth modifiers are capable of altering the morphology, size, and/or structure of crystals, often through preferential interaction with different crystallographic facets. , Modifiers are typically decorated with functional groups (motifs) that have a strong binding affinity to crystal surface sites (kinks, step edges, or terraces) where they impede solute attachment via distinct modes of action , that alter anisotropic rates of growth with concomitant impact on crystal shape . Citric acid (CA) is a common modifier of numerous minerals, such as calcium oxalate monohydrate and calcium carbonate, ,− and is an active component in formulations used to prevent pipe corrosion. − Citrate is also commonly used as a capping agent for materials such as silver (Ag) and gold (Au) nanoparticles to elicit tailored crystal morphologies. − An analogue of citrate, hydroxycitrate (HCA), has also been found to be an effective inhibitor of calcium-based crystallization through a unique strain-induced mechanism. − …”

Role of Additives in Crystal Nucleation from Solutions: A Review

“…173,184 These three inhibitors have been shown to more effectively stop COM. 213 Whether CA respectively stabilizes the amorphous phase and potentially inhibits the nucleation still needs more exploration. 214 However, it has been found that the increase in urine pH after potassium citrate treatment can lead to calcium phosphate kidney stones.…”

“…documented that citrate interacted with polynuclear stable complexes and amorphous precursors to restrain calcium oxalate nucleation. Hsu and his coauthors have shown that 500 ppm of HCA can induce unstable triclinic calcium oxalate trihydrate (COT), 1.5 ppm phytate, or 20 ppm chondroitin sulfate can induce the metastable tetragonal calcium oxalate dihydrate (COD). These three inhibitors have been shown to more effectively stop COM .…”

Role of Hyaluronic Acid on the Nucleation Kinetics of Calcium Oxalate Hydrates in Artificial Urine Quantified with Droplet Microfluidics

“…39 In other studies that used artificial urine as a solvent, Hsu et al investigated the nucleation kinetics of CaOx using a batch crystallizer in the presence of various additives in synthetic urine. 40 Cerini et al worked on nucleation of CaOx in urine with the additive of albumin, leading to COD formation particularly. 41 Polat and Eral characterized CaOx crystals forming in a well-mixed liter size crystallizer in water and artificial urine media.…”

“…Gardner and Nancollas observed that sodium pyrophosphate exhibited a strong inhibiting effect on COM growth in water . In other studies that used artificial urine as a solvent, Hsu et al investigated the nucleation kinetics of CaOx using a batch crystallizer in the presence of various additives in synthetic urine . Cerini et al worked on nucleation of CaOx in urine with the additive of albumin, leading to COD formation particularly .…”