102
3 Methods
1. Mix 2.5 mg of SDS in 1 mL CD 3 OD/D 2 O and sonicate it for
15 min (see Note 1) in order to form micelles.
2. SDS concentration (400 mM) must exceed the critical micelle
concentration of 8.2 mM in order to ensure micelle formation
and the applied molar ratio of 5 mM captopril/400 mM SDSD25 (1:80) must be used to establish the immersion of at least
one drug molecule in the micellar aggregate, assuming an SDS
aggregation number of at least 60 monomers. The sample is
then transported to a 600 μL NMR tube.
3. Use increasing quantities of 5-DSA in the sample in order to
examine its concentration-dependent effects. Every addition
contains 5 μL and after four additions, the molar ratio of drug
to the spin label is 1:1 (see Note 2).
4. NMR data were collected on a Varian INOVA 600 MHz spectrometer (Slovenian NMR Centre at National Institute of
Chemistry) using pulse sequences and phase cycling routines
provided in spectrometer library of pulse programs (see Note
3). The
1
H spectral width was set to 5679.8 Hz according to
the range of
1
H resonances of captopril.
5. The ROESY experiment was recorded with 4096 data points in
t 2 , 238 complex points in t 1 , 32 scans, a relaxation delay of
1.5 s, and a 4 kHz spin-locking field strength. A mixing time of
150 ms was used according to our previous studies in SDS
micelle environment [19–22] (see Note 4).
6. Experiments were run right after the preparation and at stable
temperature (see Notes 5 and 6).
4 Results and Discussion
In Fig. 2 is shown the
1
H NMR spectrum of captopril in SDS-d 25 /
CD 3 OD/D 2 O.
One approach for structure identification of captopril-observed
resonance peaks is of course to search if similar or identical experiment is performed in the literature. This will save time and accelerate
the search in understanding the effects of captopril in SDS-d 25 .
1
H
NMR results for captopril in D 2 O are reported by Casy and Dewar
[19] and are described in Table 1. Based on the D 2 O- reported
results the
1
H NMR chemical shifts obtained with D 2 O/CΗ 3 ΟD/
SDS-d 25 sample are easily elucidated and are shown in Table 1.
Evangelia Soumelidou et al.
3 Methods
1. Mix 2.5 mg of SDS in 1 mL CD 3 OD/D 2 O and sonicate it for
15 min (see Note 1) in order to form micelles.
2. SDS concentration (400 mM) must exceed the critical micelle
concentration of 8.2 mM in order to ensure micelle formation
and the applied molar ratio of 5 mM captopril/400 mM SDSD25 (1:80) must be used to establish the immersion of at least
one drug molecule in the micellar aggregate, assuming an SDS
aggregation number of at least 60 monomers. The sample is
then transported to a 600 μL NMR tube.
3. Use increasing quantities of 5-DSA in the sample in order to
examine its concentration-dependent effects. Every addition
contains 5 μL and after four additions, the molar ratio of drug
to the spin label is 1:1 (see Note 2).
4. NMR data were collected on a Varian INOVA 600 MHz spectrometer (Slovenian NMR Centre at National Institute of
Chemistry) using pulse sequences and phase cycling routines
provided in spectrometer library of pulse programs (see Note
3). The
1
H spectral width was set to 5679.8 Hz according to
the range of
1
H resonances of captopril.
5. The ROESY experiment was recorded with 4096 data points in
t 2 , 238 complex points in t 1 , 32 scans, a relaxation delay of
1.5 s, and a 4 kHz spin-locking field strength. A mixing time of
150 ms was used according to our previous studies in SDS
micelle environment [19–22] (see Note 4).
6. Experiments were run right after the preparation and at stable
temperature (see Notes 5 and 6).
4 Results and Discussion
In Fig. 2 is shown the
1
H NMR spectrum of captopril in SDS-d 25 /
CD 3 OD/D 2 O.
One approach for structure identification of captopril-observed
resonance peaks is of course to search if similar or identical experiment is performed in the literature. This will save time and accelerate
the search in understanding the effects of captopril in SDS-d 25 .
1
H
NMR results for captopril in D 2 O are reported by Casy and Dewar
[19] and are described in Table 1. Based on the D 2 O- reported
results the
1
H NMR chemical shifts obtained with D 2 O/CΗ 3 ΟD/
SDS-d 25 sample are easily elucidated and are shown in Table 1.
Evangelia Soumelidou et al.