Today there are many opportunities to use various tools of process analytical technologies in pharmaceutical development, manufacturing and quality assurance. The use of process analytical technology tools is encouraged by the regulatory organs in pharmaceutical industry. Since freeze drying is a very complex process, understanding the process and quality planning is the key for a successful development of a freeze-dried product. Since freeze drying process is very energy consuming the use of process analytical technologies is of great importance in its optimization.
In this master's thesis we studied the impact of critical formulation (the choice of isotonic agents and ingredients for pH adjustment) and process (addition of the annealing step and different filling volumes) parameters on lyophilisate's quality attributes (residual moisture content, specific surface area, reconstitution time and stability of the final product). Using multivariate data analysis we developed a prediction model for water content determination. We concluded that critical formulation and process parameters, both, have an impact on lyophilisate's quality attributes as well as these quality attributes also have an impact on each other. We noted that filling volume and choice of an isotonic agent have the greatest impact on residual water content in the final product. Specific surface area is influenced mostly by the addition of the annealing step and is also connected to residual water content and reconstitution time. Addition of annealing step has an impact on reconstitution time as well as on stability of the lyophilisates which also depends on residual water content. To properly understand all the relationships among the mentioned parameters the use of multivariate tools for design, data acquisition and analysis is of great importance.
Furthermore we used partial least squares method to develop a model for prediction of water content using near infrared spectroscopy. Water content is one of the critical quality attributes of the freeze-dried product and also the dynamics of water sublimation and desorption during freeze drying process are important. Near infrared spectroscopy being a fast method for water content determination can be an important tool for designing a robust process, process monitoring and quality assurance of a final product.
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