2. Nanoparticles
Nanoparticles (NPs), which are solid, colloidal
particles consisting of macromolecular substances
that are being developed to:
improve drug bioavailability
abrogate treatment-induced drug resistance
Reduce nonspecific toxicity in the field of medicine.
22
3. NANOPARTICLES DElIVERY SYSTEM
In order to optimize the therapeutic index of
antitumor drugs, Decreasing their toxicity to normal
tissues
The presence of reactive pendant groups in NPs
make easy their vectorization forward specific cell
motif by binding of ligands.
These include various ligands that bind to specific
target cell surface markers or surfacemarkers
expressed in the disease microenvironment
33
4. Responsive systems, such as pH-sensitive polymers,
are also included in this category
Hence, over the past years, efforts have been
focused on the development of nanomedicines
such as
NPs
liposomes
micelles
dendrites for the specific delivery of anticancer
drugs to tumor tissues
44
5. 2. Physiological characteristics of
Once a tumor cell cluster, whether in its initial stage
as a primary tumor or in later stages.
when forming metastases, induces an angiogenic
switch, its vasculature and microenvironment
changes dramatically
and abnormal cellular organization, vessel structure,
and physiology function develops (Figure 1).
55
solid tumors
7. 3. Targeted drug delivery
nanoparticles
Targeted NP therapeutics have shown great
potential for cancer therapy, as they provide
enhanced efficacy and reduced side effects .
NP drug delivery can be either an active or passive
process.
Passive delivery refers to NP transport through
leaky tumor capillary fenestrations into the tumor
interstitium and cells by passive diffusion or
convection. 77
8. Selective accumulation of NP and drug then occurs
by the already mentioned characteristics of the
tumor microenvironment
Active targeting involves drug delivery to a specific
site based on molecular recognition. One such
approach is to couple a ligand, such monoclonal
antibodies, lectins, aptamers, folate, and peptides, to
a NP so that the ligand can interact with its receptor
at the target cell site
88