The possibility of using x-ray powder diffraction, infrared and raman spectroscopy in the study of the identification of structural polymorphs of acetaminophen

Abstract

Paracetamol (acetaminophen), a pain-killer with antipyretic properties, shows structural polymorphism. It occurs in three polymorphic forms: Monoclinic, orthorhombic, and unstable form III. In the study, the commercially available samples of paracetamol (P1 and P2) were examined using X-ray powder diffraction, infrared, and Raman spectroscopy. Results demonstrated that all of the methods defined polymorphic forms of paracetamol in the samples. However, only Raman spectroscopy and PXRD methods detected impurities in the sample P1. These methods transpired to be more sensitive than the FT-IR method, which identified samples of paracetamol as one structural form (monoclinic polymorph). Moreover, the Raman spectroscopy identified impurities in the form P1 as changes in the crystalline form.