317
group. So SDS has amphiphilic properties, which allow this molecule to form micelles. SDS is the most widely employed micelleforming detergent for laboratory procedures [31]. Charged
detergents (including SDS) are very useful in NMR studies, where
features of these micelles such as small size are advantageous [31].
2 Materials
1. All samples for liquid NMR spectroscopy should be sufficiently
soluble in the respective deuterated solvent.
2. Usually, 5 mm tubes are used for the preparation of liquid NMR
samples. For different NMR instruments (e.g., 400, 500,
600 MHz), NMR tubes of different quality are selected as well.
In case the sample dissolves glass, a polytetrafluoroethylene
(PTFE) insert or a Kel-F (a fluorochemical product) tube is
used.
3. The researcher should take into consideration that in some
cases the cap may contaminate the sample. The cap could release
materials (for example when CDCl 3 or DMSO-d6 is used). The
researcher should avoid this possibility by closing the tube with
Teflon tape and afterwards with the tube’s cap [32].
4. In case the sample is air sensitive, a vacuum or an inert atmosphere is required. Special NMR tubes are commercially available. Rarely the removal of oxygen is necessary, so the sample
should be prepared under argon [32].
5. Samples for ssNMR spectroscopy are placed into rotors made
by ZrO 2 . The most common types of rotors are (a) 80 μL for
solids and (b) 50 and 12 μL for semisolids [32]. For the last
two, special inserts (made from Teflon or Kel-F) are used. The
usage of inserts is necessary, if the sample is soft or contains a
liquid.
6. Researchers should avoid contamination of the sample with skin
lipids (oils), which results in NMR signals under magic-angle
spinning (MAS) experiments.
All materials for liquid NMR experiments were stored at 4 °C.
1. D 2 Ο (99%+).
2. Sodium dodecyl-d 25 sulfate was 98% [CD 3 (CD 2 ) 11 OSO 3 Na]
pure (Fig. 1).
All materials for ssNMR experiments were stored at 4 °C.
1. Irbesartan (IRB—Fig. 1) was kindly provided by Prof.
M. Koupparis (National and Kapodistrian University of Athens).
2.1 General Practical
Aspects
2.2 Materials
for Liquid NMR
Experiments
2.3 Materials
for ssNMR
Experiments
NMR Techniques Applied to Drug: Cyclodextrin Complexation
group. So SDS has amphiphilic properties, which allow this molecule to form micelles. SDS is the most widely employed micelleforming detergent for laboratory procedures [31]. Charged
detergents (including SDS) are very useful in NMR studies, where
features of these micelles such as small size are advantageous [31].
2 Materials
1. All samples for liquid NMR spectroscopy should be sufficiently
soluble in the respective deuterated solvent.
2. Usually, 5 mm tubes are used for the preparation of liquid NMR
samples. For different NMR instruments (e.g., 400, 500,
600 MHz), NMR tubes of different quality are selected as well.
In case the sample dissolves glass, a polytetrafluoroethylene
(PTFE) insert or a Kel-F (a fluorochemical product) tube is
used.
3. The researcher should take into consideration that in some
cases the cap may contaminate the sample. The cap could release
materials (for example when CDCl 3 or DMSO-d6 is used). The
researcher should avoid this possibility by closing the tube with
Teflon tape and afterwards with the tube’s cap [32].
4. In case the sample is air sensitive, a vacuum or an inert atmosphere is required. Special NMR tubes are commercially available. Rarely the removal of oxygen is necessary, so the sample
should be prepared under argon [32].
5. Samples for ssNMR spectroscopy are placed into rotors made
by ZrO 2 . The most common types of rotors are (a) 80 μL for
solids and (b) 50 and 12 μL for semisolids [32]. For the last
two, special inserts (made from Teflon or Kel-F) are used. The
usage of inserts is necessary, if the sample is soft or contains a
liquid.
6. Researchers should avoid contamination of the sample with skin
lipids (oils), which results in NMR signals under magic-angle
spinning (MAS) experiments.
All materials for liquid NMR experiments were stored at 4 °C.
1. D 2 Ο (99%+).
2. Sodium dodecyl-d 25 sulfate was 98% [CD 3 (CD 2 ) 11 OSO 3 Na]
pure (Fig. 1).
All materials for ssNMR experiments were stored at 4 °C.
1. Irbesartan (IRB—Fig. 1) was kindly provided by Prof.
M. Koupparis (National and Kapodistrian University of Athens).
2.1 General Practical
Aspects
2.2 Materials
for Liquid NMR
Experiments
2.3 Materials
for ssNMR
Experiments
NMR Techniques Applied to Drug: Cyclodextrin Complexation