This document proposes a novel approach to modeling tablet film coating processes. It notes that film coating is commonly used to protect drugs, mask tastes, and control drug release profiles, but current batch processes can lead to problems and inconsistency. The proposed approach aims to provide a more holistic model that links macroscale parameters to microstructural processes, addressing weaknesses of prior approaches that considered only isolated aspects or lacked predictive power. This would help manufacturers reduce costly trials and support regulatory compliance by improving process understanding.

1. A novel approach to modelling
of tablet film-coating
Michael Lu, Joy Phophichitra
Dr Axel Zeitler

2. Motivation
Coated tablets are the dominant drug dosage form
Benefits: protect drug, mask taste, uniformity,
appearance, release profile
Batch process: Tablets are sprayed in a rotating drum
Complex multi-parameter system

3. Motivation
Many problems occur on a regular basis

4. Motivation
Better process understanding – basis for future process
improvement
Benefits of improved modelling:
Manufacturer - reduce expensive and time-consuming
trials
Regulator - compliance with FDA’s recent “quality by
design” initiative

5. Weaknesses of
Current approaches
Thermodynamic
models
Empirical
studies
Discrete element
model (DEM)
simulations
Limited
predictive power
No description of
film-forming
phenomena
Semi-empirical
Cannot translate
between coating
units
Many trials required
Most papers
concentrate on
isolated aspects
Large
computational
expense
Ray-tracing
spray coating
algorithm

6. Novel approach
“An all-encompassing model for film coating has not been
developed yet. In fact, one probably never will be.”
Ebey, 1987

7. Entire process had never been combined before:
Demonstrates holistic approach is possible
Links macroscale parameters to microstructural
processes
Large scope for further work and collaboration