192
3. Before loading the sample and the reference cell, make sure that
they are clean (see Note 5).
4. Load the reference cell with H 2 O (see Note 6).
5. Load the HP-β-CD (1 mM) into the sample cell using a glass
syringe trying to avoid air bubble formation (see Note 7).
Approximately, 250 μL of sample solution is needed.
6. Load losartan (25 mM) in the titration syringe. The instrument
will automatically load and degas the drug solution. A volume
of 70 μL is enough for the syringe loading.
7. Put the automated syringe into the sample cell (see Note 8).
8. Follow the same procedure to run a control experiment by
titrating 25 mM of losartan potassium into buffer (see Note 9).
1. Set temperature at 25 °C (see Note 10).
2. Set the DP to 6 μcal s
−1
(see Note 11).
3. Set the number of injections to 17 (see Note 12)
4. Set the volume of the first titration to 0.4 μL and the duration
at 0.8 s.
5. Set the volume of the remaining 16 injections to 2 μL and their
duration to 0.8 s.
6. Set the spacing between the injections to 200 s (see Note 13).
7. Set the filter period to 3 s.
8. A moderate stirring is sufficient for the mixing of a cyclodextringuest system.
9. Check the high feedback mode to elicit higher sensitivity.
1. Process the raw data of each experiment (Fig. 1, upper panels of
a and b) in order to integrate the area of each injection. Obtain
the plot that provides the area of each injection as kcal per mole
of injectant against the molar ratio of the two interactants at
each time point (Fig. 1, lower panels of a and b).
2. When losartan is injected into the HP-β-CD or the buffer solution, endothermic events are observed in both cases. However,
the absorbed heat in the HP-β-CD–losartan interaction is much
less than the one that is required for the losartan’s dilution into
the buffer solution (see Note 14).
3. Subtract the data of the control experiment from the data of the
HP-β-CD–losartan interaction (Fig. 2). After the subtraction,
the negative enthalpy change that originates from the interaction is revealed indicating that the inclusion of losartan into the
HP-β-CD cavity is an exothermic process.
4. Exclude the first injection from the data points (see Note 15).
3.3 Run Parameters
3.4 Data Analysis
Maria V. Chatziathanasiadou et al.
3. Before loading the sample and the reference cell, make sure that
they are clean (see Note 5).
4. Load the reference cell with H 2 O (see Note 6).
5. Load the HP-β-CD (1 mM) into the sample cell using a glass
syringe trying to avoid air bubble formation (see Note 7).
Approximately, 250 μL of sample solution is needed.
6. Load losartan (25 mM) in the titration syringe. The instrument
will automatically load and degas the drug solution. A volume
of 70 μL is enough for the syringe loading.
7. Put the automated syringe into the sample cell (see Note 8).
8. Follow the same procedure to run a control experiment by
titrating 25 mM of losartan potassium into buffer (see Note 9).
1. Set temperature at 25 °C (see Note 10).
2. Set the DP to 6 μcal s
−1
(see Note 11).
3. Set the number of injections to 17 (see Note 12)
4. Set the volume of the first titration to 0.4 μL and the duration
at 0.8 s.
5. Set the volume of the remaining 16 injections to 2 μL and their
duration to 0.8 s.
6. Set the spacing between the injections to 200 s (see Note 13).
7. Set the filter period to 3 s.
8. A moderate stirring is sufficient for the mixing of a cyclodextringuest system.
9. Check the high feedback mode to elicit higher sensitivity.
1. Process the raw data of each experiment (Fig. 1, upper panels of
a and b) in order to integrate the area of each injection. Obtain
the plot that provides the area of each injection as kcal per mole
of injectant against the molar ratio of the two interactants at
each time point (Fig. 1, lower panels of a and b).
2. When losartan is injected into the HP-β-CD or the buffer solution, endothermic events are observed in both cases. However,
the absorbed heat in the HP-β-CD–losartan interaction is much
less than the one that is required for the losartan’s dilution into
the buffer solution (see Note 14).
3. Subtract the data of the control experiment from the data of the
HP-β-CD–losartan interaction (Fig. 2). After the subtraction,
the negative enthalpy change that originates from the interaction is revealed indicating that the inclusion of losartan into the
HP-β-CD cavity is an exothermic process.
4. Exclude the first injection from the data points (see Note 15).
3.3 Run Parameters
3.4 Data Analysis
Maria V. Chatziathanasiadou et al.