[Development of an NMR-Based Molecular Characterization Platform for Quality Assessment of Pharmaceutical...

Understanding the molecular-level properties of pharmaceutical formulations is essential for optimizing drug dissolution, stability, and delivery performance. In recent years, the structural complexity of formulations has increased significantly, incorporating multiple functional excipients. In this context, NMR spectroscopy has emerged as a powerful tool for evaluating the physicochemical behavior of active pharmaceutical ingredients (APIs) and excipients across diverse formulation platforms. NMR enables non-destructive, high-resolution analysis of molecular states under various physical conditions, including solids, solutions, and suspensions. Through techniques such as NMR relaxometry, pulsed-field gradient (PFG) NMR, and advanced pulse sequences, NMR provides insight into molecular mobility, miscibility, intermolecular interactions, and phase behavior. These molecular characteristics are closely related to key formulation attributes such as physical stability, dissolution performance, and bioavailability. This review outlines the principles and methodological advances in applying NMR to pharmaceutical formulation research, emphasizing its ability to quantify and differentiate complex coexisting states in situ. By offering direct access to critical molecular information, NMR serves as a diagnostic tool and a foundation for rational formulation design and quality control. As formulation strategies continue to evolve, the role of NMR in guiding the development and evaluation of innovative drug delivery systems is expected to become increasingly important.