THE UNDERLYING FACTS AND PRINCIPLES.
Phosphoric acid forms three salts with sodium, as follows :H3PO4, phosphoric acid.NaH2PO4, mono-sodium-phosphate.Na2HPO4, di-sodium-phosphate.Na3PO4, tri-sodium-phosphate.The mono- and the di-sodium phosphate normally occur in the urine. Uric acid is readily soluble in di-sodium phosphate, but it is not soluble in mono-sodium phosphate. The addition, in fact, of mono-sodium phosphate to a solution of uric acid in di-sodium phosphate will cause the precipitation of the uric acid.It is clear, therefore, that the solubility of uric acid in the urine is enhanced by the presence of di-sodium phosphate and that the tendency to the formation of uric acid concretions increases in proportion to the amount of mono-sodium phosphate that is excreted through the kidneys.It is also clear that any endeavor directed toward preventing the precipitation of uric acid in the urinary passages must be concerned with increasing the amount of
CROFTAN AC. THE ADMINISTRATION OF CALCIUM SALTS IN NEPHROLITHIASIS DUE TO URIC ACID CALCULI.. JAMA. 1903;XL(13):818-820. doi:10.1001/jama.1903.92490130002001a