The design of a commercial manufacturing process that meet all of these requirements requires the careful characterization of the coating formulation, and the development of in depth understanding of how its properties impact the ultimate performance of the drug product.
This is the basis for many ongoing "quality-by-design" initiatives in both pharmaceutical and Food industry that are intended to:
1. Increase the efficiency of manufacturing processes and reduce materials and money wastes,
2. To develop both a product which is designed to meet customer's needs and performance requirements,
3. To develop process which is designed to consistently meet product critical quality attributes.
Thus a “quality by design” approach will then result in an in-depth understanding of the interactions of the several variables such as coating–carrier raw materials (Density, Molecular Weight, Glass Transition…), coating solution (Viscosity, Surface Tension…), manufacturing (Process Used, Process Variables…) and environmental conditions (Storage Temperature and RH…), etc. and facilitate manufacturing of a coated particle. The general aim of this is to obtain the desired quality-functionality of the coating starting from the complete knowledge of the coating polymer. With these ideas in mind, we use both a different investigation criteria and a completely new setup fluid bed coating experiments, which encompass the advantages of the afore-mentioned approach.
The idea underlying our new setup is simple: controlling and recording all the relevant variables (Fluid Bed Temperature first of all before-during-after a single experiment, Inlet Air flow rate and temperature, Coating Solution spraying rate…) we can directly relate end-product performance, manufacturing parameters and storage conditions. Factorial Design approach has been used to estimate the overall main factor effects and the interaction between different variables. Accurate analysis of the results and the comparison with the characterization of the raw materials (done by means of up-to-date techniques) provides the ability necessary to design manufacturing processes that optimize the desired performance properties.