Visualising liquid transport through coated pharmaceutical tablets using Terahertz pulsed imaging.

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Chemical Engineering

Background:

• Coated pharmaceutical tablets present complex dissolution challenges due to their layered structure.
• Understanding coating-matrix interactions is crucial for optimizing drug release and formulation design.

Purpose of the Study:

• To investigate the penetration of dissolution medium into coated tablets using terahertz pulsed imaging.
• To elucidate the role of coating structure and tablet core properties on liquid transport and drug release.

Main Methods:

• Utilized terahertz pulsed imaging (TPI) to visualize liquid ingress into coated tablets.
• Employed a model system of microcrystalline cellulose cores coated with Opadry II (PVA-based).
• Coating was applied via vacuum compression molding to flat-faced tablets.

Main Results:

• Successfully resolved coating hydration and liquid penetration into the tablet core.
• Identified density discontinuity at the coating-core interface, with coating polymer entering the core's surface pores.
• Demonstrated that tablet core porosity influences coating quality and dissolution performance (r=0.6932).
• Observed evidence of a gel layer formation upon coating polymer hydration.

Conclusions:

• Terahertz pulsed imaging provides a valuable tool for studying tablet coating-liquid interactions.
• Coating structure and core porosity are critical factors influencing dissolution.
• This methodology can enhance the understanding and optimization of coated tablet formulations.