(260c) An Integrated Model for the Thermodynamics of the Film Coating Operation the Mixing Phenomena in the Drum and the Distribution of Properties in the Coated Tablet

The film coating operation is a versatile step in the manufacture of solid dosage forms of drug product in the pharmaceutical industry. The coat applied to a drug product can be required for either pure elegance purposes (non-functional coat), or to determine critical functionality of controlled release dosage form; it may also be used to coat the drug itself onto a core carrier. The distribution of the coating material for a functional coating is a critical quality parameter due to the direct link with the release of drug from the tablet. For non-functional coatings, the distribution (and level) of condensable components into the tablet core can play a critical role in the long term physical and chemical stability of the product.

In a previous work we presented a dynamic model of the film coating system that aimed at considering all the transient energy and mass transport phenomena that occurs during the execution of a given recipe for this process. This contribution describes the modeling of the mixing phenomena inside the coater. The mixing model was validated with data acquired with a digital video system and tracer tablets for 20 experiments for coaters from laboratory scale to large-scale commercial manufacture. The parameters of the mixing model are in line with prior knowledge about the mixing behavior of tablet beds. Furthermore, the mixing model was coupled with the dynamic thermodynamic model to provide a holistic modeling approach to the film coating operation where the distribution of the properties of the coated tablets (e.g. coating content, water absorbed and coating thickness) can be predicted as a function of the operating recipe.