Abstract
The present contribution is focused on the research activity carried out in cooperation with Novartis Pharma S.p.A., finalized to the determination of the thermodynamic equilibrium conditions for the crystallization system made of the three components water (W) - acetone (A) - D, where D is the active ingredient (deferoxamine) of a commercial save-life drug (Desferal®).
The ternary system W-A-D is characterized by the complete miscibility of the system W-A, and the insolubility of D in A. The addition of acetone to the aqueous solution involves, therefore, a reduction of the solubility of D in the bi-component solution W-A with the consequent precipitation of D (formation of a solid bottom layer). The solid phase obtained at the end of the crystallization operation is typically filtered. Some batch productions are often characterized by the formation of a crystalline solid of not well-suited properties (so called “thin crystallization”), resulting in an increased filtration time of mother waters and requiring usually a crystal re-solubilization, with lengthening of the process times and reduction of the total yields.
Tests were directed to comprise the phenomena responsible for “thin crystallization”, orienting the productions towards the “normal crystallization”. The ternary diagram with equilibrium isotherms for the system W-A-D in the interval of composition and temperature of interest (-5°C, +5°C) was assessed.
