Characterization of different laser irradiation methods for quantitative Raman tablet assessment

Area of Science:

• Pharmaceutical Sciences
• Analytical Chemistry
• Spectroscopy

Background:

• Quantitative analysis of active pharmaceutical ingredients (APIs) in intact pharmaceutical tablets is crucial for quality control.
• Sub-sampling and tablet density variations pose challenges for spectroscopic methods.
• Raman spectroscopy offers a non-destructive approach for chemical analysis.

Purpose of the Study:

• To investigate quantitative Raman spectroscopy for assessing APIs in immediate-release tablets.
• To evaluate the impact of laser irradiation patterns and sub-sampling on accuracy.
• To determine the influence of tablet density on Raman spectroscopic measurements.

Main Methods:

• Quantitative Raman spectroscopy was applied to intact pharmaceutical tablets.
• Four different laser irradiance patterns were tested to assess sub-sampling effects.
• Univariate and multivariate data analysis techniques were employed.
• UV absorbance spectroscopy served as the reference method.
• The effect of tablet compression force (density) was investigated.

Main Results:

• The best prediction error (1.7%) was achieved using multivariate calibration with multiplicative signal correction (MSC) and large-area laser irradiation.
• Quantitative Raman assessment was rendered insensitive to tablet density variations within a 5-20 kN compression range with appropriate data treatment.
• Sample heating effects were discussed in relation to irradiation patterns.

Conclusions:

• Quantitative Raman spectroscopy is a viable technique for laboratory analysis and Process Analytical Technology (PAT) in pharmaceutical manufacturing.
• Optimized irradiation strategies and advanced data processing can overcome challenges like sub-sampling and density variations.
• This study provides a foundation for implementing Raman spectroscopy in pharmaceutical quality control.