Calcium oxalate monohydrate crystal (COM)

Calcium oxalate monohydrate crystal (COM), chemical formula CaC₂O₄·H₂O, is the most thermodynamically stable form of calcium oxalate and a principal component of most human kidney stones[1][2][3][4][6]. COM crystals are colorless or white, monoclinic, and highly insoluble in water[1][3][4]. Their formation and growth, particularly in urine and renal tissues, are influenced by factors such as pH, supersaturation, presence of inhibitors (like citrate), and additives (such as natural or synthetic polysaccharides)[2][5][6]. COM is not a therapeutic target in the sense of being a receptor, enzyme, or transporter, but it is a pathogenic crystal whose formation is modulated in strategies to prevent kidney stone disease. Interfering substances—including polyanions and citrate—can inhibit crystal growth or promote other, less pathologic hydrates[6]. COM possesses cytotoxic potential and can injure renal epithelial cells, partly dependent on its morphology and surface properties[2]. Its relevance is therefore indirect in therapeutics—substances are developed to inhibit its formation or effects rather than to bind or modify COM as a molecular target.

Other names

Calcium oxalate monohydrateWhewelliteCaC₂O₄·H₂OCOM crystal

Inhibition of crystallization (e.g., citrate, polyanions inhibit COM crystal growth, aggregation, or nucleation)