Infrared imaging of pharmaceutical materials undergoing compaction

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Engineering

Background:

• Compaction and consolidation are critical steps in pharmaceutical manufacturing.
• Understanding heat generation during these processes is essential for tablet quality.
• Traditional methods for temperature measurement can be invasive.

Purpose of the Study:

• To employ infrared thermography as a novel, non-contact technique for real-time temperature measurement during pharmaceutical powder compaction.
• To investigate the heat released during the compaction and consolidation of pharmaceutical powders and granules.
• To assess the effects of compaction parameters on heat generation and distribution.

Main Methods:

• Utilized a high-sensitivity infrared camera (Agema Infrared Systems, Model 470) for non-contact, real-time temperature measurements.
• Captured high-resolution thermal images of tablets immediately after compaction (<1 sec).
• Investigated a model granulation blend (microcrystalline cellulose, spray-dried lactose, magnesium stearate) compressed on an instrumented rotary press.

Main Results:

• Demonstrated that heat released during compaction increases with increasing compaction force (e.g., 33.8°C at 20 kN vs. 29.5°C at 6.7 kN).
• Achieved high geometric and temperature resolution in thermal surface profiles.
• Camera readout reproducibility was found to be better than 3%.

Conclusions:

• Infrared thermography is a viable and effective non-contact method for studying heat release during pharmaceutical powder compaction.
• Compaction force is a significant factor influencing the temperature rise post-compaction.
• The technique allows for the assessment of non-homogeneous heat distribution within tablets.