Insight into molecular dynamics and thermodynamic properties of electrospun drug-loaded fibres

This study analyses the effect of metronidazole (MET) on the thermal and dynamic properties of poly(ε-caprolactone) (PCL) fibres. The investigation was conducted using differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS). DSC results revealed the presence of two glass transition temperatures, suggesting the existence of at least two distinct amorphous phases within the material. BDS analysis identified α-relaxation related to the segmental mobility of PCL and β-relaxation associated with local molecular motions. The presence of metronidazole led to a decrease in the activation energy of the β-process and modified the relaxation dynamics, indicating dynamic heterogeneity of the system and the potential for tailoring the functional properties of the material through compositional control. The study highlights the potential of such systems in drug delivery biomedical materials. • Fibres made of PCL and varying content of MET were prepared using electrospinning. • Obtained composite fibres have both crystalline and amorphous domains. • Two dielectric relaxation processes are present for fibres (α-process, β-process). • Phase transitions and occurring glass transitions were observed by DSC and BDS.