Calcium Oxalate Precipitation in Model Systems Mimicking the Conditions of Hyperoxaluria

Abstract

This work focuses on systematic research of spontaneous precipitation of calcium oxalate in model systems mimicking the chemical conditions typical for hyperoxaluria. For this purpose, model systems of three different complexities (simple, NaCl, and artificial urine system) and two initial pH (pH i = 5.0 and pH i = 9.0) at 37°C are studied. In all investigated systems, dominant precipitation of calcium oxalate monohydrate (COM) is observed, except in artificial urine system at pH i = 9.0, c i (C 2 O 4 2− ) ࣙ 6.0 mmol dm −3 and c i (Ca 2+ ) ࣙ 7.5 mmol dm −3 , where precipitation of a mixture of calcium oxalate monohydrate and calcium oxalate dihydrate occurs. The significant difference is mainly observed in COM crystal morphology. In a simple system, COM precipitates in a dendritic form; in NaCl system, dendritic form and irregular shapes are found, while in the artificial urine, prismatic hexagonal and aggregated COM crystals precipitate.

Calcium Oxalate and Gallic Acid: Structural Characterization and Process Optimization toward Obtaining High Contents of Calcium Oxalate Monohydrate and Dihydrate

“…Synthesis of calcium oxalate seeds during spontaneous precipitation process was described in detail in previous papers [23][24][25]. In this report, slightly remodelled experimental protocol has been used with addition of gallic acid in reaction solution.…”

“…In run 17, the weight loss in the first step was 8.80% and, in the second, was 10.41%, which was a total weight loss of 19.21%. However, because the process took place in a two-step process, a possible presence of COT is indicated, while the presence of COM and COD is demonstrated in the one-step process [23][24][25]. Moreover, in run 17, only after a detailed XRD quantitative analysis was it possible to determine which hydrate phase was present in the samples.…”

Precipitation of Calcium Oxalate Monohydrate Under Nearly the Same Initial Supersaturation

“…The procedure for calcium oxalate precipitation was discussed in detail previously. [14,19,20] The precipitation experiments were carried out in a thermostated, doublewalled glass reactor. Before initiating the experiments, reactant solutions were thermostated at the corresponding temperature (the process was carried out at 25 °C, 36.5 °C, and 48 °C).…”

Calcium Oxalate Crystallization: Influence of pH, Energy Input, and Supersaturation Ratio on the Synthesis of Artificial Kidney Stones

“…Recent studies of calcium oxalate crystallization in a batch system are investigating, inter alia, the amount of water of crystallization, depending on the supersaturation ratio. , It could be deduced that calcium oxalate monohydrate (COM) or whewellite was the predominant crystal system . Furthermore, different promoters, inhibitors, , or processes were investigated in the production of calcium oxalate. , …”