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Effect of pH variation on Raman-based quantification of active pharmaceutical ingredients: implications for model
Yusui Sato1,2, Yutaro Hirose3, Takashi Kinoshita2
1R&D Division, HORIBA, Ltd, Kanda Awaji-cho 2-6, Chiyoda-ku, Tokyo 101-0063, Japan. yusui.sato@horiba.co.jp.
Analytical Methods : Advancing Methods and Applications
|August 5, 2026
Summary
pH variations significantly impact Raman spectroscopy quantitative models for active pharmaceutical ingredients (APIs). Understanding these spectral changes is crucial for developing robust multivariate analysis (MVA) models in drug quality control.
Area of Science:
- Analytical Chemistry
- Spectroscopy
Background:
- Raman spectroscopy offers non-destructive, rapid analysis of liquid samples.
- Quantitative analysis of active pharmaceutical ingredients (APIs) is vital for drug quality control.
- Multivariate analysis (MVA) enhances accuracy in simultaneous multi-compound quantification.
Purpose of the Study:
- To investigate the impact of pH variations on Raman spectra.
- To assess the effect of pH-induced spectral changes on quantitative models for APIs.
- To provide insights for robust MVA model development in Raman-based analysis.
Main Methods:
- Preparation of model liquid formulations with varying pH.
- Acquisition of Raman spectra for these formulations.
- Construction and evaluation of MVA-based quantification models for single and multiple APIs.
Main Results:
- High quantification accuracy was achieved for APIs using MVA models.
- Systematic variations in model prediction performance were observed due to pH changes.
- pH-induced spectral variations demonstrably affect quantitative model reliability.
Conclusions:
- pH variation is a critical factor influencing Raman-based quantitative analysis of APIs.
- Accounting for pH is essential for developing reliable and robust MVA models.
- The study provides practical insights for improving drug quality control using Raman spectroscopy.
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