Characterization of melt-quenched and milled amorphous solids of gatifloxacin

Abstract

The objectives of this study were to characterize and investigate the differences in amorphous states of gatifloxacin. We prepared two types of gatifloxacin amorphous solids coded as M and MQ using milling and melt-quenching methods, respectively. The amorphous solids were characterized via X-ray diffraction (XRD), nonisothermal differential scanning calorimetry (DSC) and time-resolved near-infrared (NIR) spectroscopy. Both the solids displayed halo XRD patterns, the characteristic of amorphous solids; however, in the non-isothermal DSC profiles, these amorphous solids were distinguished by their crystallization and melting temperatures. The Kissinger–Akahira–Sunose plots of non-isothermal crystallization temperatures at various heating rates indicated a lower activation energy of crystallization for the amorphous solid M than that of MQ. These results support the differentiation between two amorphous states with different physical and chemical properties.

Keywords:

• Amorphous solid
• gatifloxacin
• non-isothermal DSC
• time-resolved near-infrared spectroscopy
• X-ray diffraction

Disclosure statement

The authors declare that they have no conflicts of interest to disclose.

Funding information

This study was performed as a project supported by “Musashino Gakuin Tokubetu Kenkyu-hi”.