Mid and Near Infrared Spectroscopy

Abstract

Vibrational spectroscopy in the mid (MIR) and near infrared (NIR) range provides structural information on virtually any organic compound and thus pre- sents many interesting perspectives in both qualitative and quantitative analysis. These two techniques are powerful analytical tools for the identification and molecular characterization of pharmaceutical raw materials, intermediates and final dosage forms. NIR spectroscopy being fast, noninvasive, multiparametric, robust and easy to interface with a process, perfectly matches the measurement system requirements within the process analytical technology (PAT) framework. This chapter focuses on modern pharmaceutical MIR and NIR applications and covers (1) basic principles of both techniques including recent advances in instru- mentation, sampling and data processing, (2) characterization of solid drug mole- cules and excipients, (3) nondestructive analysis of solid oral dosage forms, (4) secondary structural analysis of protein therapeutics, and (5) real-time process monitoring and control in drug substance and drug product manufacture. Strategies of MIR and NIR signal processing and multivariate NIR method implementation are highlighted and practical challenges of specific applications discussed. Finally, theoretical and practical aspects of NIR in vivo applications are briefly reviewed. Overall, the analytical versatility of infrared spectroscopy to be applied in various fields of pharmaceutical development, production and quality control is demon- strated and potential benefits and limitations of the distinct wavelength regions are scrutinized.