The kinetics of crystallization of uric acid dihydrate in aqueous solution with a constant ionic strength 0.3 mol dm(-3) NaCl and at thermodynamic and physiological temperature (25 and 37 degrees C) was studied using isoperibolic reaction twin calorimeter. The enthalpy of crystallization Delta H-cr = -47.3 +/- 0.9 and -46.2 +/- 1.4 kJ mol(-1)and kinetic constant k(g) = 2.0 x 10(-8) and 9.6 x 10(-8) m(4) s(-1) mol(-1) were determined at 25 and 37 degrees C, respectively. (C) 2013 Elsevier B.V. All rights reserved.