171
tively, are 185 °C and 270 °C, while 2-HP-β-CD has been
reported to melt at a broad range, from around 20 °C to
150 °C [9, 14, 15].
9. A high heating rate may not allow for certain kinetic phenomena to appear and as a result should not be too high. Based on
the bibliography, 10 °C min
−1
is appropriate for
cyclodextrin:sartan system analysis [9, 12, 15, 16].
10. Constant pressure is essential in this type of calorimetry, in
order to monitor the heat capacity of the sample under constant pressure (C p ).
11. Each analysis may be normalized per total sample, per cyclodextrin, or per sartan mass, depending on which DSC peak is
studied. For example, in a physical mixture of 2-HP-β-CD and
irbesartan, a certain amount of drug is probably not complexed and will melt because of its crystalline state. In cases of
complexes and mixtures, certain peaks may reflect one material or both materials in their complexed form and as a result
should be analyzed appropriately (Fig. 4).
12. A lot of other parameters that concern the calorimetric profiles
are available to extract; however, these are the most utilized in
the bibliography [11, 14, 16].
13. The baseline may vary each time it is set. For this reason, three
different attempts should be made, in order to extract a statistical sample for the enthalpy change ΔH. This does not apply
on other thermodynamic parameters that are more accurate.
14. During analysis, the baseline might deviate from its original
horizontal, due to kinetically slow endothermic or exothermic
phenomena or because of the measurement itself. In case we
wish to include this deviation during peak integration, we have
to set the baseline accordingly. In this way, comparisons
between peaks and areas that contain these peaks are attainable. An example is given below (Fig. 5).
15. The enthalpy change ΔH is considered negative for an endothermic process and positive for an exothermic process.
Acknowledgments
We gratefully thank Prof. G. Valsami and E. Christodoulou for
their help to prepare the complexes. This work has been cofinanced by the European Union and Greek national funds through
the program “Support for Researchers with Emphasis on Young
Researchers” (call code: EDBM34, ΚΕ 14995) and under the
research title “Preparation and study of innovative forms of administration of pharmaceutical molecules targeting at improved pharmacological properties.”
DSC on Sartan/Cyclodextrin Delivery Formulations
tively, are 185 °C and 270 °C, while 2-HP-β-CD has been
reported to melt at a broad range, from around 20 °C to
150 °C [9, 14, 15].
9. A high heating rate may not allow for certain kinetic phenomena to appear and as a result should not be too high. Based on
the bibliography, 10 °C min
−1
is appropriate for
cyclodextrin:sartan system analysis [9, 12, 15, 16].
10. Constant pressure is essential in this type of calorimetry, in
order to monitor the heat capacity of the sample under constant pressure (C p ).
11. Each analysis may be normalized per total sample, per cyclodextrin, or per sartan mass, depending on which DSC peak is
studied. For example, in a physical mixture of 2-HP-β-CD and
irbesartan, a certain amount of drug is probably not complexed and will melt because of its crystalline state. In cases of
complexes and mixtures, certain peaks may reflect one material or both materials in their complexed form and as a result
should be analyzed appropriately (Fig. 4).
12. A lot of other parameters that concern the calorimetric profiles
are available to extract; however, these are the most utilized in
the bibliography [11, 14, 16].
13. The baseline may vary each time it is set. For this reason, three
different attempts should be made, in order to extract a statistical sample for the enthalpy change ΔH. This does not apply
on other thermodynamic parameters that are more accurate.
14. During analysis, the baseline might deviate from its original
horizontal, due to kinetically slow endothermic or exothermic
phenomena or because of the measurement itself. In case we
wish to include this deviation during peak integration, we have
to set the baseline accordingly. In this way, comparisons
between peaks and areas that contain these peaks are attainable. An example is given below (Fig. 5).
15. The enthalpy change ΔH is considered negative for an endothermic process and positive for an exothermic process.
Acknowledgments
We gratefully thank Prof. G. Valsami and E. Christodoulou for
their help to prepare the complexes. This work has been cofinanced by the European Union and Greek national funds through
the program “Support for Researchers with Emphasis on Young
Researchers” (call code: EDBM34, ΚΕ 14995) and under the
research title “Preparation and study of innovative forms of administration of pharmaceutical molecules targeting at improved pharmacological properties.”
DSC on Sartan/Cyclodextrin Delivery Formulations