79
the amide group of IND, as well as at 1595 cm
−1
ascribed to
C-C stretching modes of the aromatic rings. Finally, the peak
at 760 cm
−1
may be attributed to C-Cl stretching modes [21].
The spectral fingerprint is the same for all samples prepared
with both protocols. Concluding, the appearance of new peaks
indicates the existence of indomethacin in the formulations.
The peaks are hardly observed due to the low percentage of
the encapsulated drug (20%).
Dynamic light scattering (DLS) measurements were conducted
before and after the encapsulation of the drugs into the polymeric
micelles in order to determine possible differences between the
two encapsulation protocols regarding the scattering intensity,
size, and polydispersity index values of the empty/loaded micelles.
Size is one of the most important parameters/characteristics of
nanocarriers used in drug delivery [1, 2].
DLS measurements were conducted on an ALV/CGS-3 compact goniometer system (ALVGmbH), equipped with an ALV
5000/EPP multi-τ digital correlator with 288 channels and an
ALV/LSE-5003 light scattering electronics unit for stepper motor
drive and limit switch control. A JDS Uniphase 22 mW He-Ne
laser (λ = 632.8 nm) was used as the light source. All solutions
were measured five times at each angle and the average was
taken. The solutions were filtered through 0.45 μm hydrophilic
PVDF filters (Millex-LCR from Millipore) before measurements.
The angular range for the measurements was 30–150°. Obtained
correlation functions were analyzed by the cumulant method and
the CONTIN software. The size data and figures shown below are
from measurements at 90° (see Note 9).
1. Adjust a 0.45 μm filter to a plastic syringe and add 4 mL of the
solution (see Note 10).
2. Take a RIA test tube (dimension: diameter 10 mm, height
75 mm) and remove the dust from its interior using rigorous N 2
gas flow.
3. In the dust-free test tube, put 1 ml of filtered solution and shake
it in order to remove possible impurities or remaining dust in
the test tube. Repeat this procedure one more time.
4. Add 1 mL of the solution in the test tube and place it in the
instrument for measurement.
5. Apply the above-mentioned settings in the measurement setup.
6. Measure the polymeric solutions both before and after the
encapsulation of the hydrophobic drugs.
7. Size distribution graphs from CONTIN analysis for Pluronic
F-127 solutions prepared with organic solvent protocol show
the existence of a single peak before and after the encapsulation
3.7 Dynamic Light
Scattering (DLS)
Drug Delivery: Hydrophobic Drug Encapsulation into Amphiphilic Block…
the amide group of IND, as well as at 1595 cm
−1
ascribed to
C-C stretching modes of the aromatic rings. Finally, the peak
at 760 cm
−1
may be attributed to C-Cl stretching modes [21].
The spectral fingerprint is the same for all samples prepared
with both protocols. Concluding, the appearance of new peaks
indicates the existence of indomethacin in the formulations.
The peaks are hardly observed due to the low percentage of
the encapsulated drug (20%).
Dynamic light scattering (DLS) measurements were conducted
before and after the encapsulation of the drugs into the polymeric
micelles in order to determine possible differences between the
two encapsulation protocols regarding the scattering intensity,
size, and polydispersity index values of the empty/loaded micelles.
Size is one of the most important parameters/characteristics of
nanocarriers used in drug delivery [1, 2].
DLS measurements were conducted on an ALV/CGS-3 compact goniometer system (ALVGmbH), equipped with an ALV
5000/EPP multi-τ digital correlator with 288 channels and an
ALV/LSE-5003 light scattering electronics unit for stepper motor
drive and limit switch control. A JDS Uniphase 22 mW He-Ne
laser (λ = 632.8 nm) was used as the light source. All solutions
were measured five times at each angle and the average was
taken. The solutions were filtered through 0.45 μm hydrophilic
PVDF filters (Millex-LCR from Millipore) before measurements.
The angular range for the measurements was 30–150°. Obtained
correlation functions were analyzed by the cumulant method and
the CONTIN software. The size data and figures shown below are
from measurements at 90° (see Note 9).
1. Adjust a 0.45 μm filter to a plastic syringe and add 4 mL of the
solution (see Note 10).
2. Take a RIA test tube (dimension: diameter 10 mm, height
75 mm) and remove the dust from its interior using rigorous N 2
gas flow.
3. In the dust-free test tube, put 1 ml of filtered solution and shake
it in order to remove possible impurities or remaining dust in
the test tube. Repeat this procedure one more time.
4. Add 1 mL of the solution in the test tube and place it in the
instrument for measurement.
5. Apply the above-mentioned settings in the measurement setup.
6. Measure the polymeric solutions both before and after the
encapsulation of the hydrophobic drugs.
7. Size distribution graphs from CONTIN analysis for Pluronic
F-127 solutions prepared with organic solvent protocol show
the existence of a single peak before and after the encapsulation
3.7 Dynamic Light
Scattering (DLS)
Drug Delivery: Hydrophobic Drug Encapsulation into Amphiphilic Block…