Phase transitions in sugars and protein systems: Study of stability of lysozyme in amorphous sugar matrices

Abstract

In the last decades, development of products resulting from the application of molecular biology and biotechnology has demonstrated accelerated progress; as a result, the use of biological products such as proteins and enzymes has increased considerably in the food and pharmaceutical industry (Wanh 2000). Since most of these biomolecules, particularly enzymes, are extremely sensible to changes in temperature, pH, ionic force, and water concentration, scientists in these fields are in constant search of new methodologies and techniques to improve their stability. In industrial processes, biomolecules are obtained in aqueous solutions; however, in this medium their shelf life is relatively short. A remarkable improvement in the stability of protein based drugs has been obtained when these biomolecules are taken to a dry state; unfortunately, the freeze drying or spray-drying processes (which are the most common used techniques to obtain dry protein) expose these molecules to extreme conditions that cause a considerable decrease in their activity (Passot et al. 2005; Liao et al. 2004; Hinrichs et al. 2001; Heller et al. 1999).