Utility of Fourier Transform-Raman and Fourier Transform-Infrared Diffuse Reflectance Spectroscopy for Differentiation of Polymorphic Spironolactone Samples

Spectral Methods for the Characterization of Polymorphs and Solvates

“…This behavior may be contrasted with that noted for spironolactone, for which no evidence was found for the existence of enolic tautomers in any of the four polymorphs. 26 When a carbonyl group is present in a compound, the energy associated with its stretching mode is often reflective of any structural or conformational polymorphism. In fosinopril sodium, the energies of two equivalent carbonyls were similar in the two polymorphic forms, but the energy of the third carbonyl (present in nonequivalent side chains) was found to differ in the two forms.…”

Mechanistic insight into the evaporative crystallization of two polymorphs of nitrofurantoin monohydrate

“…Spectroscopic techniques have demonstrated a high potential in polymorph identification and quantification, and also in process monitoring and control [30][31][32][33][34][35][36][37][38][39]. Traditional microscopy provides direct and fast identification of morphology, and when combined with Raman spectroscopy the physical information in terms of the internal structure of crystals can be obtained at the same time.…”

Recent Advances in the Analysis of Steroid Hormones and Related Drugs

“…Conventional IR spectrometry using fused KBr discs is not suitable for their differentiation due to the easy transformation of the polymorphs under pressure. On the basis of diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and Fourier transform Raman spectroscopic investigations supported by DSC and TGA measurements 40 four different polymorphic forms 41 and five solvates 42 were identified and characterized. FT-IR studies combined with all of the above mentioned solid-phase techniques revealed the existence of three polymorphs of fluocinolone acetonide 43 as well as two polymorphs and a hemihydrate of flunisolide.…”