Thermal analysis of proteins of pharmaceutical interest

Calorimetric Study of Inulin as Cryo- and Lyoprotector of Bovine Plasma Proteins

“…The enthalpy change involved in the overall heat-induced reactions within the protein molecules, Hc, was determined by integrating the area beneath the exothermic peak and above a straight baseline drawn between the beginning and end of the transition temperature range [22,32,33].…”

“…It is noteworthy that amorphous materials are stable in the glassy state below Tg, when the temperature is higher the viscosity decreases and thus the rate of chemical reactions increases and crystallization events occur, increasing the rate of deterioration during storage [22,25,[27][28][29]. Both transitions T´g and Tg are important parameters in the development of the freezedrying cycle because not only ensures the stability and quality of the product, but also allow to improve the efficiency of the manufacturing process [20,22,28,30].…”

“…In the freeze-dried sample, water is removed and the solute concentration in the matrix increases, obtaining a material with an amorphous structure that exhibits a glass-rubber transition at a specific temperature which is named as the glass transition temperature (Tg) [24][25][26][27][28]. It is noteworthy that amorphous materials are stable in the glassy state below Tg, when the temperature is higher the viscosity decreases and thus the rate of chemical reactions increases and crystallization events occur, increasing the rate of deterioration during storage [22,25,[27][28][29]. Both transitions T´g and Tg are important parameters in the development of the freezedrying cycle because not only ensures the stability and quality of the product, but also allow to improve the efficiency of the manufacturing process [20,22,28,30].…”

“…The curve for the glass transition temperature (Tg) is reached when the solution is overcooled (B-C) until the T´g in point C, where the concentration of the vitrification agent (saccharide) is given by C´g. Then the water is eliminated and the solute concentration increases (C-D-E), obtaining a solid with an amorphous structure that exhibits a glass transition temperature (Tg) [22,28].…”

“…Below this temperature a glassy state that behaves as an amorphous solid is obtained. If the temperature of the frozen system rises above the T´g, the material becomes less viscous and freeze-drying may cause the loss of the porous structure and the product collapse [20,22,23]. In the freeze-dried sample, water is removed and the solute concentration in the matrix increases, obtaining a material with an amorphous structure that exhibits a glass-rubber transition at a specific temperature which is named as the glass transition temperature (Tg) [24][25][26][27][28].…”