Biomedical Engineering Reference
In-Depth Information
2.2 Materials
for Characterizing
Nanoparticles
0.2
m Millipore filter is useful for filtering distilled and de-ionized
water. Zetasizer Nano ZS (Malvern
®
Instruments, Westborough,
MA, USA) can be used for determining the particle size.
2.2.1 Materials
for Particle Size
μ
Aluminum stubs are required for sample loading in scanning elec-
tron microscope (SEM) and carbon-coated grids are required for
transmission electron microscope (TEM). 2 % w/v uranyl acetate or
ammonium molybdate solution is used as a negative stain for TEM
(
see Note 2
) and a flexible plastic membrane (Parafilm
®
) can be
used for transferring the nanoparticles onto carbon-coated grids.
2.2.2 Materials
for Morphology
Disposable folded capillary cells (Malvern
®
Instruments, Westbor-
ough, MA, USA) are required for measuring zeta potential
(
see Note 3
). Zetasizer Nano ZS (Malvern
®
Instruments, Westbor-
ough, MA, USA) can be used for measuring the zeta potential.
2.2.3 Materials for Zeta
Potential
Organic solvents like DCM or chloroform and aqueous solvents
like distilled and de-ionized water or Tris-EDTA buffer (TE buffer)
or 70:30 acetonitrile-water mixture are required.
2.2.4 Materials for Drug
Loading
Phosphate-buffered saline (PBS) pH 7.4, a dialysis membrane
(Spectra/Por
®
1-7 regenerated cellulose membranes, Spectrum
Laboratories, Inc, CA) with a molecular weight cut off in the
range of 6,000-50,000 Da (
see Note 4
) and sodium azide.
2.2.5 Materials for In
Vitro Drug Release
1 ml syringe and 30 or 32G needles.
2.2.6 Materials
for Syringeability
and Injectability
5 ml glass vials, rubber stoppers, and aluminum caps.
2.2.7 Materials for
Physical Stability
3 Methods
3.1 Preparation
of Nanoparticles
Various materials and methods can be employed to prepare nano-
particles of diverse sizes, morphologies, and compositions. Nano-
particles can be broadly classified as reservoir and matrix type
delivery systems [
10
]. Reservoir systems consist of a drug core,
which is surrounded by a polymer layer that controls drug release
[
11
,
12
]. Matrix type of systems have the drug distributed through-
out a polymeric carrier [
10
]. Although there are some reports on
the preparation of reservoir type systems of a nanoscale [
13
], matrix
type systems are more commonly prepared, due to the ease of their
preparation. While aseptic manufacturing of nanoparticles using
sterile raw materials is ideal, depending on the drug stability in
