Digital tool development – Modelling Recrystallization of Amorphous Lactose
Elsa Björling1, Henrik Berggren1, Ingela Niklasson Björn1, Julien Giovannini1, Duy Nguyen1
1AstraZeneca Gothenburg, Pepparedsleden1, 431 84, Mölndal, Sweden
Summary
The need for more digital tools to support development and manufacturing has increased a lot in all types of industries in the last decades, the pharma industry is no exception. In this study, a modelling tool has been developed to support the process of recrystallization of amorphous powders. This is of particular interest for inhalation due to the impact of residual amorphous on stability or aerosolization performance of products.
In this work, the crystallization of amorphous lactose was simulated and compared with isothermal microcalorimetry, TAM (Thermal Activity Monitor) experiments. The driving force for recrystallization used the difference between the glass transition temperature (TG) of the amorphous lactose and the operating process temperature, T. The Gordon & Taylor equation is used to describe the composition dependence of the transition temperature. The Guggenheim–Anderson–de Boer (GAB) equations with parameters fitted for the different states of lactose are utilized in this study to estimate saturated moisture content at different humidity levels. The crystallization kinetics used are the ones proposed by Bronlund [1], namely Avrami-Bronlund.