Film coating density and thickness: Critical quality attributes for immediate release tablet disintegration control

Area of Science:

• Pharmaceutical Sciences
• Materials Science

Background:

• Immediate release (IR) film coatings are designed for rapid drug release.
• However, these coatings can transiently impede water transport, affecting tablet hydration and subsequent drug dissolution.
• Understanding factors influencing tablet hydration is crucial for optimizing drug delivery systems.

Purpose of the Study:

• To investigate the impact of coating density and thickness on tablet hydration kinetics.
• To explore the relationship between coating attributes and drug release rates.
• To identify key parameters for controlling tablet disintegration and drug release.

Main Methods:

• Utilized polyvinyl-alcohol-based Opadry II coatings on placebo tablets.
• Manipulated spray application parameters to create varying film attributes.
• Employed terahertz (THz) surface reflection to determine coating density via refractive index.
• Applied terahertz pulsed imaging (TPI) to assess hydration and dissolution rates.

Main Results:

• A direct correlation was found between refractive index and coating density.
• Both coating density and thickness significantly influenced hydration and dissolution rates.
• Coating density emerged as a more critical factor than simple weight gain in determining hydration and dissolution behavior.

Conclusions:

• Precise control over coating parameters during film coating is essential for predictable tablet disintegration and drug release.
• Coating density is a key determinant of tablet hydration and dissolution kinetics, offering a more reliable control parameter than weight gain alone.
• This study highlights the importance of optimizing coating density for immediate release formulations.