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1. “POLYMERIC NANOPARTICLES
FOR TARGETED DELIVERY”
By:
Dr. A. R. Kulkarni,
Assoc. Professor,
Dept of Pharmacology,
K.L.E.S’s College of
Pharmacy,
Belgaum-10
2. “POLYMERIC NANOPARTICLES
FOR TARGETED DELIVERY”
By:
Dr. A. R. Kulkarni,
Assoc. Professor,
Dept of Pharmacology,
K.L.E.S’s College of Pharmacy,
Belgaum-10
3. Contents
• Introduction to targeted drug delivery system
• Bioavailability, efficiency, efficacy
• Volume of distribution v/s drug toxicity
• Drug receptor concept
• Nature of receptors
• Site specificity
• Antigen- Antibody mechanism
• Advantages of targeting
• Mechanism of targeting
• Classifications of targeting
• Importance of transport system
• Polymeric nanoparticles
4.
5. Introduction to Targeted Drug Delivery System
Definition:
‘Targeted drug delivery’
Carriers, They are drug vectors,
Bioavailability
F = Bioavailable dose
Administered dose
Bioavailability – Absolute v/s Relative
7. Ideal systemic delivery vector
• Non-toxic vehicle
• Non-immunogenic
• Condensation of DNA
• Intracellular delivery
• Targeting ligand
• Stabilization of particles
8. Carrier systems used for targeted drug delivery:
1. Colloidal carriers
a) Vesicular systems
Liposomes, niosomes, pharmacospheres, virosomes.
b) Microparticulate system
Microparticles, nanoparticles, magnetic microspheres
2. Cellular carriers
Released erythrocytes, serum albumin, antibodies, platelets
3. Supramolecular delivery systems
Micelles, reverse micelles, mixed micelles, polymeric micelles
4. Polymer based systems
Signal sensitive, mucoadhesive, biodegradable, bioerodable
5. Macromolecular carriers
a) Proteins
b) Glycosylated water soluble polymers
c) Toxins, immunotoxin and rCD4 toxin conjugates
d) Lectins and polysaccharides
10. Drug receptor concept
• Binding of drugs to receptors necessarily obeys
the Law of Mass Action
• At equilibrium, receptor occupancy is related to
drug concentration by the Hill- Langmuir
equation
• The higher the affinity of the drug for the
receptor, the lower the concentration at which it
produces a given level of occupancy
11. • The same principles apply when two or more
drugs compete for the same receptors, each
has the effect of reducing the apparent affinity
of the other
12. Site specificity
• Drug is a chemical that affects physiological
function in a specific way
• With few exceptions drugs act on target
proteins namely- enzymes, carriers, ion
channels, receptors
• Specificity is reciprocal: individual classes of
drug bind only to certain targets, & individual
targets recognize only certain classes of drug
13. • No drugs are completely specific in their action
• In many cases, increasing the dose of a drug
will cause it to affect targets other than the
principal one, and this can lead to side-effects
15. Mechanism of targeting
• Passive targeting
• Active targeting
• Inverse targeting
• Physical targeting
• Dual targeting
16. Active targeting further classified into…
1. First order targeting
Refers to restricted distribution of the drug carrier
system to the cappilary bed of a predetermined
target site, organ or tissue
Ex. Compartmental targeting in lymphatics, peritoneal cavity, plural cavity,
lungs, joints
2. Second order targeting
Refers to selective delivery of drugs to a specific cell
type such as tumor cells & not the normal cells
Ex. The selective drug delivery to the Kupffer cells in the liver exemplifies
this approach
17. 3. Third order targeting
Refers to drug delivery specifically to the internal
(intracellular) site of target cells
18. Physical targeting
• This is selective drug delivery programmed &
monitored at the external level (ex-vivo) with the
help of physical means
• In this mode of targeting , some characteristics
of the environment are used to direct the carrier
to a particular location or to cause selective
release of its contents
20. Factors affecting the biodistribution
of nanoparticles
• Surface hydrophobicity:
The higher the nanoparticle hydrophobicity, the faster
the nanoparticles are removed from the circulation
and taken up by the cells of the MPS
• Surface charge:
Negative surface charge increases the clearance of
nanoparticulates, relative to neutral or positively
charged surfaces
21. • Surface size:
Nanoparticles more than 5000 nm are normally
entrapped in the capillary network of the lungs
Nanoparticles less than 100 nm may be able to leave
the circulation through gaps or fenestrations in the
endothelial cells lining the blood vessels
22. Polymeric nanoparticles
• As the name suggests polymeric nanoparticles
are nanoparticles which are prepared from
polymers
• In recent years these have attracted
considerable attention as potential drug
delivery devices in view of their applications in
- drug targeting to particular organ/tissue
- as carriers of DNA in gene therapy
- ability to deliver proteins, peptides and genes
through per oral route of administration
23. • In spite of various synthetic & semisynthetic
polymers, natural polymers still enjoy their
popularity
- gums (ex. Acacia, guar, etc.)
- chitosan
- gelatin
- sodium alginate
- albumin
• Polymer used must be chemically inert, non-
toxic and free of leachable impurities
• It must have appropriate physical structure,
with minimal undesired aging & be readily
processable
24. • Polymers dsigned for medical applications are
designed to degrade within the body
- polyactides (PLA)
- polyglycolides (PGA)
- poly (lactide-co-glycolides) (PLGA)
- polyanhydrides
- polyorthoesters
- polycyanoacrylats
- polycaprolactone
• Advantage of degradable polymers- they are
broken down into biologically acceptable
molecules that are metabolized and removed
from the body via normal metabolic pathways
25. Fact:
• Abraxane is first polymeric nanoparticle based
product from American Pharmaceutical
Partners, Inc., and American Bioscience, Inc.
(ABI)
• It was approved in the year 2005 and is
consisting of albumin bound paclitaxel
nanoparticles
26. Emulsion polymerization
• In this method, the monomer is dispersed in
aqueous solution as a uniform emulsion and
stabilized by the surfactants.
• Dispersion of the surfactant persists until the
critical micellar concentration (CMC) is
realized.
• The anionic polymerization of
polyalklycyanoacrylate monomers into
polymeric NPs follows the emulsion
polymerization technique.
PRODUCTION OF NANOPARTICLES BY
DIFFERENT TECHNIQUES
27. • Dispersion polymerization
NPs of polyacrylamide (PAM) by the dispersion
polymerization of acrylamide monomer at 40°C.
They used the partial isopropyl ester derivative of
poly(vinyl methyl ether-alt-maleicanhydride)
(PVME-alt-MA), called PVME-co-MA-co-iPrMA, as
the stabilizer, and ammonium persulfate (APS) as
the initiator.
• Solvent diffusion and evaporation
Water insoluble polymers can be used for
production of NPs.
28. • The in vivo biodistribution of NPs is greatly
influenced by their interactions with the plasma
proteins.
• Opsonization by plasma proteins renders the NPs
more vulnerable to mononuclear phagocytotic
attack, mainly by the Kupffer cells of the liver.
• In fact, the main disadvantage of drug targeting to
the CNS is the rapid uptake of NPs by the
macrophages of the RES, thus hindering NP
applications in controlled drug delivery and drug
targeting, to tissues other than those of the RES.
SURFACE MODIFICATION OF NANOPARTICLES
29. • Therapeutic drug levels of the targeted (e.g., brain)
drug-loaded NPs are therefore difficult to reach.
Tween-80
• It was demonstrated that substances which could not
otherwise cross the BBB, can induce permeability
when the substance is bound onto the surfaces of
poly (cyanoacrylate) nanoparticles, and coated with
surfactants, such as Tween-80.
• It seemed that brain targeting of nanoparticles was
concerned with the interaction between Tween-80
coating and brain micro-vessel endothelial cells.
30. • Kreuter et al have extensively discussed the
nanoparticle mediated drug transport to the brain
overcoated with polysorbates and other surfactants.
Polyethylene glycol
• The presence of the hydrophilic coating on the
surface of the nanoparticles is thought to sterically
stabilize them against opsonization and phagocytocis.
• Among the hydrophilic polymers, polyethylene glycol
(PEG) has been found to be a particularly effective
steric stabilizer, probably due to its high
hydrophilicity, chain flexibility, electrical neutrality and
absence of functional groups, which prevent
interactions with the biological components in vivo.
31. • The NP surface coating with hydrophilic polymers such
as PEG has been shown to confer long circulation
properties to poly(lactide) (PLA), poly(lactide-co-
glycolide) (PLGA), poly (caprolactone) (PCL) and poly
(phosphazene) and poly(cyanoacrylate) nanoparticles.
Poloxamer/Poloxamine
• The drug-loaded NPs were surface-modified with block
copolymers of the poloxamer 407 or poloxamine 908
series, and administered intravenously to rats under
study.
• It was demonstrated that the blood circulation half-life
was increased by its encapsulation in the surface-
modified NPs (25-30 min), whereas uncoated NPs
rapidly cleared from the blood (only 8 % remaining after
5 min).
32. • Additionally, the amount of NPs in the liver was found to
significantly decrease after NPs encapsulation within the
modified NPs.
• Similar correlations were made regarding decreases in
splenic uptake of coated nanoparticles. Thus, PLGA
nanoparticles successfully escaped capture by the RES.
35. Effects of the CS-γ-PGA NPs on the TEER values of
Caco-2 cells.
+
Chitosan
+
+
+
+
+
+
+
+
+
γPGA
Nanoparticles with a positive surface charge
were able to reduce the values of TEER.
Time (hr)
TEER
of
Initial
Value
(%)
1 2 3
0 4
20
40
60
80
100
120
Control Group 0.01% -PGA:0.05% CS
0.10% -PGA:0.20% CS
0.20% -PGA:0.01% CS
(n = 3)
Removal of
Nanoparticles
Time (hr)
TEER
of
Initial
Value
(%) 0 4 8 12 16 20 24
20
40
60
80
100
120
Removal of
Nanoparticles
Control Group 0.01% -PGA:0.05% CS
0.10% -PGA:0.20% CS
0.20% -PGA:0.01% CS
(n = 3)
Figure 2. Effects of the prepared CS–-
PGA nanoparticles on the TEER values of
Caco-2 cell monolayers.
38. we have developed paclitaxel-loaded formulations using the
nanoparticles for the treatment of cancers.
Paclitaxel is one of the most active anticancer drugs
introduced in cancer chemotherapy
Even though paclitaxel is prescribed mainly to treat breast
and ovarian cancers, it is known that various cancer cells
including hepatoma cells can be killed effectively by this
drug
PACLITAXEL- LOADED NANOPARTICLES
39. Nanoparticles may be delivered to specific sites
by size-dependant passive targeting or by active targeting
Hepatoma cells are known to recognize galactose-
and N-acetylgalactosamine-terminated glycoproteins
via the asialoglycoprotein (ASGP) receptors located on
their surfaces
Galactosylated Nanoparticle
Galactosamine
40. Synthesis of γ-PGA-PLA block copolymers
PGA produced by Bacillus licheniformis (ATCC 9945,
Bioresources Collection and Research Center, Hsinchu,
Taiwan) and purified
Block copolymers composed of PGA and PLA were
synthesized using CDI to activate the terminal hydroxyl
group of PLA
Galactosamine was conjugated to the paclitaxel-loaded
nanoparticles via an amide linkage by EDC
41. OH
C
O
CH
CH3 n
PLA
O
CH2 O O
C
O
CH
CH3 n
O
CH2 O C N
O N
-PGA
m
NH
CH
CH2
CH2
C
C
O OH
O
NH2
OH
Amphiphilic
Block Copolymer
N
N C N
O N
Galactosylated Nanoparticle
Galactosamine
CDI
Activated PLA
46. Incubation for 1 day
Cells were fixed with 3.7% formaldehyde in PBS cells
were stained with Oregon Green and propidium iodide
(PI, Sigma) that specifically bind to F-actin and the
nucleus, respectively.
Additionally, microtubule networks were revealed using a
monoclonal anti-bovine -tubulin, with an anti-mouse
IgG-Alexa Fluor 633 (Molecular Probes).
Immunofluorescence analysis
52. CONCLUSIONS
Drug-loaded nanoparticles with galactosamine
conjugated prepared in the study can effectively target
the site of tumor via the ASGP receptor-mediated
recognition and significantly reduce its size
Polymeric nanoparticles are the promising
candidates to deliver drugs / peptides
53.
54.
55. Acknowledgements
• Prof. T. M. Aminabhavi, CEPS, Dharwad
• Prof .P. V. Kulkarni, and Dr. Celeaste,
SWMC, Dallas
• Prof. Sung and Dr. Fafa, National Tsing
Hua University, Taiwan
