A Step Towards Real-Time Release Testing of Pharmaceutical Tablets: Utilization of CIELAB Color Space

Area of Science:

• Pharmaceutical manufacturing
• Process analytical technology (PAT)

Background:

• The pharmaceutical industry is transitioning towards real-time release testing (RTRT).
• RTRT relies on continuous data collection for release decisions.
• Spectroscopic technologies are favored for continuous direct compression due to speed and non-destructive nature.

Purpose of the Study:

• To demonstrate the feasibility of using CIELAB color space for monitoring tablet porosity and tensile strength.
• To evaluate UV/Vis diffuse reflectance spectroscopy as an in-line tool for real-time quality assessment.

Main Methods:

• Five different tablet formulations were processed with varying particle sizes and deformation properties.
• Compression forces ranged from 3 to 18 kN.
• In-line CIELAB color space measurements were taken using a UV/Vis probe during tablet ejection.

Main Results:

• Increased compression force reduced tablet surface roughness and porosity, while increasing tensile strength.
• These physical changes correlated with alterations in the tablet surface's reflection properties, specifically the C* chroma value.
• Linear relationships were established between compression force, physical tablet properties, and measured color values for all formulations.

Conclusions:

• UV/Vis diffuse reflectance spectroscopy combined with CIELAB color space transformation is a viable tool for real-time release testing.
• This method allows for in-line monitoring of critical tablet quality attributes like porosity and tensile strength.
• The findings support the integration of PAT for enhanced pharmaceutical manufacturing control.