Evaluation of activation energy conformity derived from modelfree non-isothermal predictions and Arrhenius isothermal results The case of hydrochlorothiazide–lactose reaction

In this study, the activation energy of HCTZ–
lactose interaction was determined and compared to
isothermal and non-isothermal methods. DSC data were
fitted to different thermal models such as Friedman, Flynn–
Wall–Ozawa and Kissinger–Akahira–Sunose, and the
activation energy was calculated subsequently. Isothermal
studies were performed by heat ovens, and analysis was
done using high-performance liquid chromatography
technique, and the activation energy (Ea) were calculated
according to Arrhenius method. To date, no practical
evaluations has been performed in the literature on the
conformity of these different heating methods in incompatibility studies. The kinetic data obtained from the
isothermal and non-isothermal methods showed no significant difference. The current study demonstrated a good
conformity between the isothermal and non-isothermal
kinetic results, and thus, it can be suggested that DSCbased kinetic analysis can provide a simple, reliable and
fast comparative data in the kinetic evaluation of an
incompatibility seen in early stages of preformulation
studies. Finally, the advantages and drawbacks of each
method are fully discussed.