Chemical Basis Of The Structurally-Specific Potassium Aminocarboxylates On Crystallization Of Calcium Oxalate

The effects of potassium carboxylates and aminocarboxylates on the crystallization of calcium oxalate (CaOxa) were investigated using SEM, FT-IR and XRD in silica gel with a double diffusion technique. The studied carboxylates included potassium tartrate (K₂Tart) and potassium citrate (K₃Cit); aminocarboxylates included potassium aminoacetate (Kgly), dipotassium glycoletherdiaminotetraacetate (K₂EGTA), dipotassium aminotriacetate(K₂NTA), dipotassium diethylenetriaminepenteacetate(K₂DTPA), dipotassium ethylene diaminetetra-acetate (K₂EDTA) and dipotassium cyclohexanediamine tetraacetate (K₂CDTA).For mixed carboxylates, the mixed K₂EDTA and K₂Tart or K₃Cit with various proportions could either induce more calcium oxalate dihydrate (COD) and trihydrate (COT), or decrease the size of monohydrate (COM), or make COD and COT stabilize for longer time. It demonstrated the mixed carboxylates had better inhibitive effect than any of the single. K₂EDTA-K₃Cit could induce twisted COD crystals, which looked like the morphology of the COD grown in healthy human urine and had a less (100) crystal face, could decrease the retention and adhesion of COD with the surface of renal tubular cells.For single aminocarboxylates, K₂EDTA and K₂CDTA could decrease the specific surface area of COM aggregates and change the morphology of COD, K₂NTA and K₂DTPA could inhibit the aggregation of COM strongly and induce the formation of COD with small size, whereas Kgly and K₂EGTA had no significant effects. The ability to inhibit the aggregation of COM followed: K₂DTPA > K₂NTA > K₂CDTA > K₂EDTA > K₂EGTA > Kgly. The ability to induce COD followed: K₂DTPA(55%) > K₂EDTA ≈ K₂CDTA (50%) > K₂NTA(43%) >> K₂EGTA(4%) ≈ Kgly(2%). The inhibition abilities increased as increasing their concentrations except Kgly and K₂EGTA. The ability to prevent the gel-mediated phase transformation of COD followed: K₂NTA > K₂EDTA > K₂DTPA > K₂CDTA >> Kgly≈ 0.For mixed aminocarboxylates, mixed K₂NTA-K₂EDTA used clinically could decrease the surface area of COM, but could not increase content of COD; mixed K₂DTPA-K₂NTA could only promote nucleation of COD; plate-like COM and large content of COD were found in mixed K₂EDTA-K₂DTPA system, which had obvious cooperative action.These results demonstrated single K₂NTA or K₂DTPA and mixed K₂EDTA-K₃Cit or K₂EDTA-K₂DTPA might be beneficial to the prevention and cure of urinary stones.