Physical aging of 2 types of PEO could be tracked by the combination of PALS, DSC, and SEM methods. After storing the samples a 40°C ± 2°C and 75% ± 5% RH, a decrease in the o-Ps lifetime values and an increase in the melting enthalpies as a function of storage time indicated a reorientation of the polymer chains. The limitations of monitoring enthalpy relaxation confirm the importance of methods that track volume relaxation, such as PALS. Structural changes could be observed even after a short storage time (4 weeks), which highlights the effect of further investigations of the influence of physical aging on the properties of PEO-containing dosage forms.
- Differential scanning calorimetry
- Physical aging
- Poly(ethylene oxide)
- Positron annihilation lifetime spectroscopy
ASJC Scopus subject areas
- Pharmaceutical Science