Naslov
Thermal analysis of paracetamol polymorphs by FT-IR spectroscopies

Autori
Zimmermann, Boris ; Baranović, Goran

Izvornik
Journal of pharmaceutical and biomedical analysis (0731-7085) 54 (2011), 2; 295-302

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
polymorphism; infrared; spectroscopy; paracetamol; thermal; amorphous

Sažetak
A simple IR spectroscopy based methodology in routine screening studies of polymorphism is proposed. Reflectance and transmittance temperature dependent IR measurements (coupled with the 2D-IR data presentation and the baseline analysis) offer a positive identification of each polymorphic phase, therefore allowing simple and rapid monitoring of the measured system. Applicability and flexibility of the methodology was demonstrated on the measurement of the model polymorphic compound paracetamol under various conditions (geometric constraints and elevated pressure). The thermal behavior of paracetamol strongly depends on slight variations in experimental conditions that can result in formation of various phases (three polymorphs and the amorphous form). The amorphous phase can crystallize during heating into either Form II or Form III within almost identical temperature range. Likewise, the crystal transformations II→I and III→II also can proceed within almost identical temperature range. Furthermore, the thermal behavior is even more diverse than that, and includes the crystallizations of Form I, II and III from the melt, and the high temperature II→I transition. The variety of the temperatures of the transformations is a major obstacle for unambiguous identification of a particular phase by DSC and a major reason for the implementation of these IR methods.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA