Analysis of large-scale tablet coating: Modeling, simulation and experiments

Area of Science:

• Pharmaceutical engineering
• Chemical engineering
• Process simulation

Background:

• Industrial-scale tablet coating requires precise control of process parameters.
• Ensuring uniform coating (low inter-tablet coating variation) is critical for product quality.
• Discrete Element Method (DEM) offers a powerful tool for simulating complex particulate processes.

Purpose of the Study:

• To investigate the influence of key process parameters on inter-tablet coating variation (cv,inter) in industrial drum coaters.
• To validate the use of Discrete Element Method (DEM) for large-scale tablet coating simulation.
• To determine optimal parameters for achieving uniform tablet coating efficiently.

Main Methods:

• Full-scale Design of Simulation Experiment (DoSE) using Discrete Element Method (DEM) and the eXtended Particle System (XPS).
• Modeling tablets using the glued sphere approach (eight spheres per tablet).
• Simulation of up to 290kg of material (over 1 million tablets) in an industrial drum coater.

Main Results:

• Increasing the number of nozzles and decreasing the spray rate significantly reduced inter-tablet coating variation (cv,inter).
• Drum load and rotation rate influenced tablet velocity but had minimal impact on cv,inter and process time.
• Simulated process time for uniform coating correlated well with experimental data.

Conclusions:

• DEM simulations accurately represent industrial-scale tablet coating processes.
• Spray rate and nozzle count are the most influential parameters for controlling coating uniformity.
• Simulation-driven optimization can enhance efficiency and quality in pharmaceutical coating operations.