Quantitative analysis of the layer separation risk in bilayer tablets using terahertz pulsed imaging

Area of Science:

• Materials Science
• Pharmaceutical Engineering
• Non-destructive Testing

Background:

• Layer separation is a significant defect in bilayer tablets, impacting product quality.
• The root causes and reliable detection methods for layer separation remain under-investigated.
• Existing analytical methods have limitations in predicting or distinguishing separation risk.

Purpose of the Study:

• To evaluate bilayer tablets with varying layer separation tendencies using terahertz pulsed imaging (TPI).
• To compare TPI's effectiveness against traditional methods like tensile strength, friability testing, SEM, and XRCT.
• To establish TPI as a tool for quality control in bilayer tablet manufacturing.

Main Methods:

• Bilayer tablets with different separation tendencies were fabricated and analyzed.
• Terahertz pulsed imaging (TPI) was employed for non-destructive crack detection.
• Comparative analysis included friability testing, tensile strength, SEM, and XRCT.

Main Results:

• Friability testing correlated layer separation risk with final compression pressure.
• TPI successfully detected interfacial cracks and quantified adhesion integrity via an 'interface index'.
• The interface index correlated well with separation tendency, distinguishing batch quality, unlike SEM and XRCT.

Conclusions:

• TPI provides a non-destructive, quantitative method to assess bilayer tablet interface quality and predict layer separation risk.
• TPI offers superior discrimination of separation risk compared to SEM and XRCT.
• TPI enhances understanding of compression pressure effects on interface quality, aiding robust tablet development and quality control.