Solubility and Mechanism of Dissolution of Dihydrated and Anhydrous Uric Acid

The solubilities of dihydrated orthorhomblc and anhydrous monocllnic forms of uric acid (UA) have been Investigated spectrophotometrlcally at different temperatures (2.6-50.0 °C). Data have also been collected for the different solubilities as a function of pH and have been assigned to the different species of uric acid In protolytic equilibrium at the Investigated conditions. The kinetics of uric acid dissolution Into aqueous media have also been Investigated under different experimental conditions and the results have been Interpreted In order to characterize the mechanisms Involved In the dissolution step as well as In the reverse process. Equilibrium thermodynamic quantities have been derived and their values have been discussed with reference to the proposed mechanisms.