1. K . G A U T H A M R E D D Y
2 0 1 1 A 8 P S 3 6 4 G
NANOPARTICLES IN
DRUG DELIVERY

2. INTRODUCTION
Various nanoforms have been attempted as drug
delivery systems
 Biological substances - albumin, gelatin and
phospholipids for liposomes.
 Chemical substances - Superparamagnetic NPs
and solid metal-containing NPs

3. ORGANIC NANOPLATFORMS
Liposomes
 Liposomes are self-assembled artificial vesicles
developed from amphiphilic phospholipids.
 The ability to entrap both hydrophilic and
hydrophobic drugs
Biocompatibility, Biodegradability
 Advantage: Liposome properties, such as size,
surface charge and functionality, can be easily
tuned through the addition of agents to the lipid
membrane .

5. Polymer NP
 Polymeric NPs are colloidal particles with a size range of
10–1000 nm
 Fabricated using biodegradable synthetic polymers,
such as polycaprolactones or natural polymers, such as
albumin, gelatin
Methods : solvent evaporation, spontaneous
emulsification, solvent diffusion etc have been used to
prepare the NPs.

6. Smart polymer NP
Stimuli-sensitive polymer which can change its
physicochemical properties in response to
environmental signals.
Physical (temperature, ultrasound, light, electricity
and mechanical stress), chemical (pH and ionic
strength) and biological signals (enzymes and
biomolecules)

7. copolymers answering multiple stimuli
Advantage: High sensitivity in response to a given
stimulus within a narrow range, leading to more
accurate in drug delivery.

8. INORGANIC PLATFORMS
Super paramagnetic nanoparticles
 The superparamagnetic NP are used to guide
microcapsules in place for delivery by external
magnetic fields.
Another advantage of using magnetic NPs is the
ability to heat the particles after
internalization, which is known as the hyperthermia
effect.

9. Super paramagnetic nanoparticles in controlled drug delivery
Affect the permeability of microcapsules by applying external
oscillating magnetic fields and releasing encapsulated
materials
 Controlled release of substances by applying an external
magnetic field.

10. Integrated nanocomposite particles
Each type of nanoparticle has unique advantages
and limitations.
By combining the specific function of each
material, new hybrid nanocomposite materials can
be fabricated.

11.  Liposomes are routinely coated with a hydrophilic
polymer, such as PEG or poly ethylene oxide, to
improve the circulation time in vivo
 The combination of liposomes and dendrimers has
resulted in higher drug loading , as compared with
pure liposomes

12. TARGETING STRATEGIES
Passive targeting
 Tumor vessels are highly disorganized and dilated
with a high number of pores, resulting in enlarged
gap junctions between endothelial cells .
Migration of macromolecules up to 400 nm in
diameter into the surrounding tumor region.

13.  One of the earliest nanoscale technologies for
passive targeting of drugs was based on the use of
liposomes.
 Liposomes are coated with a synthetic polymer
that protects the agents from immune destruction
 The microenvironment surrounding tumor tissue, is
different from that of healthy cells which supports
passive targeting

14. • Based on the high metabolic rate of fast-growing tumor
cells, they require more oxygen and nutrients.
Consequently, glycolysis is stimulated to obtain extra
energy, resulting in an acidic environment.
• Taking advantage of this, pH-sensitive liposomes have
been designed to be stable at physiological pH 7.4, but
degraded to release drug molecules at the acidic pH.
• Disadvantage:The passive strategy is further limited
because certain tumors do not exhibit an EPR
effect, and the permeability of vessels may not be the
same throughout a single tumor.

15. Active targeting
One way to overcome the limitations of passive
targeting is to attach affinity ligands that only bind
to specific receptors on the cell surface to the
surface of the nanocarriers by a variety of
conjugation chemistries.
Nanocarriers will recognize and bind to target cells
through ligand–receptor interactions

16. CONCLUSIONS
 Advances in this area have allowed some
nanomedicines in the market to achieve desirable
pharmacokinetic properties, reduce toxicity etc