The hot stage polarizing microscope combines thermal analysis and polarization microscopy techniques, and has become a key tool of characterization of pharmaceutical polymorphism. This instrument enables in-situ research on drug polymorphs, and reveals differences in their physicochemical properties, including crystal identification (such as crystal and amorphous forms), crystal habit analysis, polymorph screening, phase transition kinetics (melting, recrystallization, solid-state phase transition), desolvation behavior, and thermal stability. This article is based on the crystal form control requirements in drug development, combined with relevant regulatory requirements and practical research experience, to systematically expound the application strategy of hot stage polarizing microscope in the study of drug polymorphism, in order to provide reference for the characterization of drug solid morphology, process optimization, and quality control.

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