The nucleation parameters such as critical radius, volume free energy change and critical free energy barrier have been evaluated for deuterated L-arginine trifluoroacetate crystals on the basis of the classical homogeneous nucleation theory. Solution stability was studied by observing the metastable zone width employing a polythermal method and it revealed that the deuterated solution has a larger metastable zone width than its non-deuterated solution. Induction periods for different saturated solutions were also determined based on isothermal method. A good quality crystal has been successfully grown by optimizing its nucleation parameters, and its etching studies illustrated that the crystal grows in a two-dimensional nucleation mechanism. (C) 2010 Elsevier B.V. All rights reserved.