Quantitative evaluation of the sensitivity of library-based Raman spectral correlation methods

Area of Science:

• Analytical Chemistry
• Pharmaceutical Sciences
• Spectroscopy

Background:

• Library-based Raman spectral correlation is vital for pharmaceutical raw material verification.
• Current methods lack adequate evaluation of sensitivity to contaminants, especially in excipients.
• Economically motivated adulteration of excipients with similar properties is a significant concern.

Purpose of the Study:

• To develop and apply a novel approach for evaluating the sensitivity of Raman spectral correlation methods to contaminants.
• To assess the impact of contaminant properties on detection limits in binary systems.

Main Methods:

• Utilized a hit-quality index model to assess contaminant sensitivity in library-based Raman spectral correlation.
• Examined three specific excipient/contaminant binary systems: glycerin/diethylene glycol, propylene glycol/diethylene glycol, and lactose/melamine.

Main Results:

• Determined contaminant detection sensitivities of 18% (glycerin/diethylene glycol), 32% (propylene glycol/diethylene glycol), and 4% (lactose/melamine).
• Correlated these sensitivities with minimum detectable contaminant compositions for verification and identification.
• Identified relative Raman scattering cross-section as the primary factor influencing measurement sensitivity.

Conclusions:

• The hit-quality index model effectively quantifies the sensitivity of Raman spectral correlation to contaminants.
• Sensitivity is highly dependent on the specific contaminant's Raman scattering properties.
• Results provide critical insights for optimizing surveillance applications in the pharmaceutical industry.