pharmacy

1. NANOPARTICLES IN
NEUROLOGIC
DRUGS
By Dr. apt. Ika Yuni Astuti, M.Si

2. SESSION TOPICS
Global view of nanoparticles
Blood-brain barrier: role & challenge
Type of nanoparticles in neurological disease
Nanoparticles in neurological drugs
Safety and Challenge of Nanoparticles
Summary

3. Figure 1. Logarithmical length scale showing size of
nanomaterials compared to biological components &
definition of 'nano' & 'micro' sizes.
Buzea, C, et al. Nanomaterials & Nanoparticles. 2007. Biointerphases (2:4). P.14
Global view of nanoparticles
• Nanoparticles are ultrafine units in the
microscopic field of few to hundreds of
nanometers, but less than a micron in size.
• Figure 1 describe the size comparison
between nanoparticle with other
nano-/micromaterial & biological
components.
• The size of nanoparticles is comparable or
even smaller than the size of cells. It’s allows
them to be designed for such functions as
binding to cell membranes, delivery of agents
into cells or across anatomic & physiologic
compartments (eg, the blood-brain barrier),
and monitoring cellular physiologic events.
• In this session, what is meant by nanoparticles
are therapeutic nanoparticles, which are used
for drug delivery & imaging.

4. Global View of Nanoparticles
 What is nanoparticle made of?
 Drug, i.e small therapeutic molecule (usually < 6 nm), protein, or
peptide, that attached to
 Nanosized carrier materials, such as polymer, carbon, lipid, and
various metals, protein, antibody, peptide

5. Global View of Nanoparticles
 Why do we need nanoparticles?
 Traditional drugs often produce low therapeutic responses and poor
safety. The diminished therapeutic efficacy due to low solubility, no
targeting, premature clearance, premature degradation, so too little
active drug at the target for too short a-time. While increase in dose
&/or dosing frequency is a limited option, due to safety problems,
adverse effect, toxicity, and undesirable immune response.
 The properties of many traditional materials change when formed
from nanoparticles. This is typically because nanoparticles have a
greater surface area per weight than larger particles which causes
them to be more reactive to some other molecules. Nanoparticle as
drug delivery system can deliver the drugs to the site of action in a
predesigned manner thereby minimizing side-effects as well as
enhancing the bioavailability of that drug.

6. Blood-Brain Barrier: Transport Challenge
a
b
Figure 2. Blood-brain barrier structure. a: Blood vessels of the human brain (Image by Dr. Jon Polimeni, [19]). The
cerebrovascular system plays an important role in normal CNS functioning i.e memory, motion, and sensation, as the pattern of
cerebral blood vessels follows the major brain circuits. b: The complexity of the BBB structure. The vascular endothelial cells
sealed by tight junctions. A basement membrane covers the endothelium surface. The pericyte is embedded in the basement
membrane. The foot of the astrocytes almost cover the outer surface of the vessels microglia, neurons & interneurons, also
interact with the BBB & help maintain tissue homeostasis.

7. FIGURE 3. A: The neurovascular unit is made up of vascular cells. The capillaries and vessel walls of the arterioles are covered by astrocytic ends. Pericytes,
astrocytes, and SMCs have innervation neurons. The blood-brain barrier (BBB) at the center of the neurovascular unit is formed by a tightly closed endothelial cell
layer that extends along the vascular tree. The BBB expresses low paracellular & transellular permeability at cerebral capillary level & along the arteriovenous
axis. B: different neurovascular unit cells regulate cerebral blood flow, BBB integrity, neurotransmitter clearance, extracellular matrix interactions, and participate
in angiogenesis & neurogenesis.

8. The sustained structure of the BBB is formed by endothelial cells of the CNS,
capillary basement membrane (BM), pericytes, and associated astrocytes. The
peculiarity of brain endothelial cells is the continuous multitude of complexes of
tight junctions (TJ) between endothelial cells in the CNS vessels resulting in
reduced vesicular/paracellular transport. The tight attachment of the feet of
astrocytes helps to maintain the barrier function. Pericytes regulate BBB-specific
endothelial gene expression and astrocyte biology, thereby playing an important
role in maintaining BBB function and integrity. The NVU helps maintain tissue
homeostasis.
Pericytes, SMCs, and endothelial cells express thousands of transcripts encoding
different transporters, receptors, active efflux pumps, ion channels, and regulatory
molecules, whose expression patterns vary based on zoning along the
arteriocapillary vein axis and cell type.

9. FIGURE 4. Major blood-brain barrier transport systems. Transport across endothelium via CMT, RMT, active efflux, and ion transport.
CMT systems mediate the transport with precise substrate specificity and directionality. Transport across pericytes: presently, details
about pericyte transporters’ cellular polarity and precise direction(s) of transport remain elusive.
Note: APOE =
apolipoproteins E;
ABC = ATP-
binding cassette.

10.  Nanomaterials that are capable of traversing the BBB on their own have the
characteristics: low molecular weight (< 400 Da), a suitable charge, log P < 2,
nonionization, eight to ten hydrogen bonds, lipophil.
 BBB shields the entry of large molecule neurotherapeutics and hydrophilic
drug molecules to the CNS. So, the therapeutic molecule that might otherwise
be effective in diagnosis and therapy of neuro disease fails to achieve therapeutic
dose at the target site due to the screening mechanism of the BBB. Typically, such
molecules are delivered directly to the brain by injection. This method provides
adequate doses and high specifity, but there are surgery-related risks such as
intracranial hemorrhage and infection.
 An integral understanding of the mechanisms of an endogenous BBB transport
system will help design effective, non-invasive shuttles across tough barriers.
Examples of such transport systems are described in Figure 5.

11. Figure 5. Schematic representation of mechanisms available for drugs transport across the BBB. A:
Carrier-MT (amino acids, nucleosides, glucose). B) Cell-mediated transport. C) RMT (Insulin, transferrin,
low-density lipoprotein, leptin). D) Adsorptive mediated transport (Albumin, other plasma proteins). E)
BBB Disruptive mediated transport (TNF α, Mannitol). F) Tight junction opening.

12. A. Carrier Mediated Transport
 Carrier-mediated transport (CMT) enables solutes such as carbohydrates, amino
acids (AA), monocarboxylic acids, hormones, fatty acids, nucleotides, inorganic ions,
amines, choline, and vitamins to cross the BBB via substrate-specific transporters.
 The CMT-based approach is to conjugate a nanocarrier-drug complex with a
specially targeted transporter substrate.
 The targeted transporter for example large neutral amino-acid transporter
(LAT1), glucose transporter (GLUT1), cationic amino-acid transporter (CAT1),
adenosine transporter (CNT2), monocarboxylic acid (MCT1), etc.
 Examples of the application of CMT to neuro-drugs: dopamine delivered to the
brain by LAT1 using L-DOPA, which comes under CMT-BBB drug-delivery
strategy. After crossing BBB, L-DOPA is converted back to dopamine within the
brain.
 CMT suffers from several limitations, including size restriction, stereoselectivity,
ligand conjugation, nonselectivity, and off-target exposure; moreover the small
molecules transported via CMT are refluxed out via efflux pumps.

13. B. Cell-mediated Transport
 Some of the circulating cells, such as erythrocytes, leukocytes, exosomes, and
neutrophils, cross the BBB spontaneously. Cell-mediated drug delivery, using living
cells and these circulating exosomes, is driving the potential discovery for use in
nanomedic chemotherapy to treat brain disease. For example, one report described
that exosomes laden with curcumin effectively enhanced cognitive function in
C57BL/6 mice inducing an in vivo Alzheimer disease model (Wang et al, 2019). In
another study, Xue and her colleagues used neutrophils as carriers, which showed a
significant increase in BBB-traversing ability (Xue et al, 2017).

14. C. Receptor-Mediated Trancytosis
 The most commonly used strategy to allow chemotherapy to pass through the BBB is
receptor-mediated transcytosis (RMT). Specific endogenous neuropeptides such as
hormones, transferrin (Tf), insulin, and lipoproteins access the brain from the blood
via RMT using specific receptors present throughout the BBB. These receptors are
highly expressed on the luminal side of endothelial cells and aid in endocytosis and
transcytosis of molecules throughout the BBB. In RMT, surface-modified NPs first bind
to the associated selective transmembrane receptor, as in, Tf binds to the transferrin
receptor (TfR).

15. D. Adsorptive-Mediated Transport
 Macromolecular drug delivery to brain-related diseases can be increased efficiently
by the adsorptive-mediated transcytosis (AMT) strategy, which delivers drugs to the
brain via electrostatic interactions between the NP-surface positive charge and the
negative BBB membrane charge. An important feature of AMT-mediated drug
delivery is that it does not affect endogenous cellular tasks like other drug delivery
methods.
 Example: -syn containing extracellular vesicles (EVs) is transported across the BBB
α
via the AMT mechanism in a parkinsonian mouse model triggered by a single
peripheral injection of LPS, and induces a microglial inflammatory response. It is
known that positively charged albumin can transport drugs to the brain via AMT.

16. E. BBB Disruptive mediated transport
 This method uses surfactants on the surface of the nanoparticles or apply an
ultrasound scanning technique. These surfactants relax the BBB by disrupting the
junctions of endothelial cells and allowing the nanoparticles to pass through the BBB.
Recent studies have shown that repeated ultrasound scans aid in the removal of
amyloid- (A ) in the rat brain without damage.
β β
F. Tight junction opening
 The nature of BBB is mainly governed by the endothelial junction site which consists
of the adherent (AJ) and TJ junctions. This close junction between the endothelial cells
of the BBB causes increased electrical resistance and truncated penetration. By
opening these tight junctions, the BBB allows nanoparticles to travel to the brain.

17.  For the majority of the current therapeutics that have high molecular
weight (Mw ≥ 500 Da)—antibodies, peptides and proteins, which
do not cross the BBB by themselves, the inability can be overcome with
carier mediated transport.
 Essential requirements of drug carriers:
1. Mutual drug/environment protection
2. Kinetics of drug release that fit therapeutic requirements
3. Drug targeting
4. Carrier retention at target until completion of drug supply
5. Stability
6. Versatility
7. Biodegradability
8. Biocompatibility
9. No to low toxicity
10.No to low immunogenicity
TYPE OF NANOPARTICLES IN NEUROLOGICAL DISEASE

18.  One of the important requirements for designing carrier / receptor mediated
drug targeting is the ability to recognize and high-affinity binding between
two partners:
1. The carrier
2. A receptor/binding site sufficiently unique to the target.
 Recognize ability is essential for high specifity.
 High-affinity binding allows the drug to be carried to a sufficiently close distance
to the binding site/ receptor.

19.  Steps in carrier-mediated drug targeting
1. Targeting at the organ level, then
2. Targeting at the cellular level, within relevan anatomic location(s) to the molecular
sit(s) of drug action
 The internalization of the drug-carrier formulation is required for drug-carriers that
are polymers carrying drugs that require intracellular cleavage of the drug-polymer
bond and/or activation by intracellular components.
 Otherwise, the internalization is not required for small and large drugs that operate
outside the cell/on the cell membrane irrespective of whether the carrier is a
polymer or a particle.

20. TYPE OF NANOPARTICLES IN NEUROLOGICAL DISEASE
1. Metal Nanoparticles
 Dysregulation of transition metal (Zn, Cu, Fe, etc) homeostasis is usually a major
influencing aspect in a number of neurodiseases  involved in several cellular
processes in the brain (function of metallo-enzymes); their concentrations is high.
 Metal nanoparticles display the dual role: therapeutic and diagnostic agent.
 Synthesis: by modifying the shape, changing the surface charge, adjusting the
particle size, and conjugating various surface ligands (used for targeting), which is
promoting its application in the field of drug delivery for neurodisease.
 For example, Yang et al. developed controlled release of H2O2 responsiveness
from gold metal-covered mesoporous silica-nanoparticles (MSN-CQ-AuNPs) for
targeted delivery of clioquinol (CQ) for Alzheimer's disease.

21. 2. Lipid Based Nanoparticles
Lipid-based NPs are created as unique platforms by changing some of the properties
of the nanosystems and adding appropriate drugs or ligands to their surface. This can
reduce side effects. Various soft lipid-based nanocurcumin formulations (cubosome,
hexosome, spongosome, and liposome) showed promising results in inhibiting neuronal
loss in Parkinson's, Alzheimer's, ALS, and Huntington's disease.
3. Hydrogel
The hydrogel formulation is designed for either systemic delivery to the brain (or local
administration) to achieve targeted action in neurodisease. Hydrogels have been
shown to be very effective in providing nerve protection. Activin B-laden hydrogels for
PD treatment showed a slow release of activin B over 5 weeks. Significant
improvement in behavior with cellular protection was observed in this study (Zhang et
al. 2018).

22. 4. Dendrimers
 Dendrimers are the smallest nanoformulations in neurodisease treatment.
 It has great potential for application in the treatment of Parkinson's and Alzheimer's because of the
strong antiamyloidogenic activity of dendrimer.
 The use of dendrimer is limited by the high cost of production and the need for an assessment of
human health consequences after prolonged dendrimer exposure.
5. Polymer Nanoparticles
 As the earliest approach in neurodisease treatment, these block-co-polymeric molecules consist of
monomers and are readily excreted without causing systemic toxicity.
 Synthetic polymers must be biocompatible and biodegradable. Examples: polylactic acid (PLA),
poly lactic-co-glycolic acid (PLGA), and PLGA-PEG.
 PLGA nanocurcumin has been shown to increase drug delivery to treat Alzheimer's disease by
reducing oxidative stress and inflammation.
 Epigalocatechin-3-gallate (EGCG) and ascorbic acid (AA) formulations loaded with PEGylated
PLGA NP demonstrated increased therapeutic effectiveness in the APP / PS1 mouse model (familial
Alzheimer disease model).

23. NANOPARTICLES IN NEUROLOGICAL DRUGS
1. Alzheimer Disease
 Nanoparticles have promised good results in the treatment of Alzheimer's disease
by carrying drugs across the BBB, targeting amyloid- production, inducing a sink
β
effect and enhancing cleansing to improve disease conditions. Although studies
related to toxicity are unclear, nanocarrier-mediated events help to describe
important molecular events of disease progression.
 In this section, we discuss NP-based developments for the diagnosis and treatment
of Alzheimer's disease along with their potential safety and toxic effects.
 Several drugs are potentially more effective in the long term and nanotechnology
could provide a useful approach for dealing with ADME of any drug.

24. NANOPARTICLES IN NEUROLOGICAL DRUGS
1. Alzheimer Disease
 Javed et al. revealed eradication of toxic amyloid- protein by AuNP-coated casein
β
treatment using an in vivo model of zebrafish (Danio rerio). NP was translocated
across the BBB of zebrafish larvae. NP further isolated intracerebral A 42 and
β
extracted toxicity by a nonspecific approach, such as the companion observed by
the analysis of behavioral pathology biomarkers, ROS, and neurological dysfunction.
AuNPs treatment ultimately restores mobility and cognitive action of A -susceptible
β
zebrafish. It can be used to eliminate the toxicity of amyloid- protein which is
β
responsible for many ND in humans.
 Chowdhury et al., showed the novel use of a hydroxyquinoline appended
polyfluorene (PFHQ), polymer that has a character- istic “amyloid like” surface
pattern in inhibition of amyloid-β aggregation.

25. NANOPARTICLES IN NEUROLOGICAL DRUGS
1. Alzheimer Disease
Drug Type of nanoparticle Finding
Cerium oxide Nanoparticle Antioxidant
Ferulic acid SLN Antioxidant
Epigallocatechin=3-gallate (EGCG)
phenol
Nanolipid Antioxidant
Thioflavin-T (ThT) PNP Charged & fluorescent biomarker;
Detect Aβ in senile plaque
clioquinol (5- chloro-7-iodo-8-
hydroxyquinoline,CQ
PNP functionalized with n-butyl
cyanoacrylate and PBCA
Curcumin PNP
Rivastagmine-PBCA NP with
polysorbate 80 coating
NP Cholinesterase inhibitor

26. NANOPARTICLES IN NEUROLOGICAL DRUGS
2. Parkinson Disease
 L-DOPA is still regarded as the standard treatment for PD.
 To our interest, dopamine-loaded PLGA NPs delivered dopamine into the brain effectively,
reduced toxicity and eventually reversed neurobehavioral insufficiencies in parkinsonian rats.
Glutathione encapsulated liposomes were found to be useful for PD treatment, which showed
neuroprotection by maintaining intracellular glutathione in neuronal cells.
 Several studies demonstrated use of gold nanoparticles for the quantitative detection of
neurotransmitters such as epinephrine, L-DOPA, α-synuclein, norepinephrine and dopamine.
 Exosomes, released from CNS and altered during the disease process, were marked as
excellent aspirants for carrying biomarkers. For instance, exosomes have been showed for the
systemic delivery of therapeutics such as exogenous siRNA and curcumin.
 Kojima et al. showed therapeutic catalase mRNA delivery by using exosomes reduced
neuroinflammation and neurotoxicity both in vitro and in vivo PD models. Application of exosomes
include the protection against neurotoxicity in an in vitro experimental model of Parkinson’s disease
by catalase mRNA delivery.

27. NANOPARTICLES IN NEUROLOGICAL DRUGS
2. Parkinson Disease
Drug Type of
nanoparticle
Finding
Nerve growth factor (NGF) bound
poly butyl cyanoacrylate
NP
L-Dopa & derivatives Liposom Better effect, fewer side effects
Physically modified saline RNS60
with charged-stabilized nanobubbles
NP suppresses the proinflammatory molecules in MPTPinduced
animal model of PD.1
coumarin-6 loaded lactoferrin
conjugated PEG-PLGA
PNP neuroprotection in Parkinson disease
Gold NP AuNPs-doped neuro-biosensor system has high
reproducibility potency, long storage stability, and
regeneration capacity.
A-Syn siRNA Exosome Intrastriatal L-dopa delivery decreases adverse side
effects associated with oral
L-dopa.

28. NANOPARTICLES IN NEUROLOGICAL DRUGS
3. Stroke
Drug Type of
nanoparticle
Finding
Triiodothyronine (T3) - PLGA-PEG PNP enhance neuroprotection
Cerium oxide NP Neuroprotective, by reduces the 3-nitrotyrosine level, which was
generally induced by peroxynitrite radical during the stroke in
rodent stroke model
Platinum NP antioxidant property which reported lowering cerebral cortex
volume and improved motor function in stroke animal model
caspase-3 inhibitor loaded transferrin NP decrease in infarct volume in ischemic brain
SiRNA loaded carbon nanotube NP potential therapeutics
Transferrin-coupled liposomes LNP promote vascular regeneration and neuroprotection via
delivering vascular endothelial growth factor (VEGF) in stroke
treatment

29. NANOPARTICLES IN NEUROLOGICAL DRUGS
4. Epilepsy
Drug Type of
nanoparticle
Finding
Carbamazepine-chitosan SLN Treatment
poly (d,l-lactide-co-glycolide)
nanoparticle loaded βcarotene
NP coated with
polysorbate-80
anticonvulsant
thyrotropin-releasing hormone (TRH) PNP introduced into the amygdala of kin- dled rats of epilepsy.
oxcarbazepine loaded PLGA NPs PNP improved its effect when compared to parent
oxcarbazepine in epileptic seizures in rodents.

30. NANOPARTICLES IN NEUROLOGICAL DRUGS
5. Multiple sclerosis
Drug Type of
nanoparticle
Finding
Ultra sized cerium oxide NP Antioxidant, and alleviates motor deficits in MS brain

31. SAFETY AND CHALLENGE OF NANOPARTICLES
 A little information is available on the potential toxic effects of nanoparticles on the
human CNS and brain.
 The toxicity of the nanomaterial depends on the size, shape, surface potential,
surface functionalization, impurities adhered to during synthesis, chemical
composition, etc.
 Based on in vitro toxicity studies on human neuroblastoma cells, Mahmoudi et al.
stated that SPION exhibits higher toxicity compared to surface functions, at the
molecular and cellular levels. This is due to the higher absorption of lipids, proteins,
vitamins and ions which results in abnormal cell composition and pH changes.
Furthermore, SPIONs-COOH triggers an increase in genes related to oxidative
stress.

32.  Several reports regarding the neurotoxicity of various nanomaterials have caused
concern for their safe application to clinical translation.
 Example: metals have both beneficial and detrimental roles in the brain. Metals play an
important role in nerve transmission, regulation of gene expression, and preserving cell
structure in humans. On the other hand, unwanted metal accumulation in the nervous
system impairs mitochondrial function, impairs enzyme activity, and stresses. It is known
that the deposition of metal ions has been observed in the nervous system of the brain in
several neurological diseases. Metals interact with proteins such as A and affect A
β β
aggregation leading to toxicity. In addition, Cu (II) and Iron (III) ions chelate with proteins
and alter the conformation results in stimulating phosphorylation and aggregation.
 To overcome this challenge, various methods have been adopted to lower the metal ion
concentration in the brain by administering chelators.

33. CONCLUSION
Neurodiseases are a serious problem worldwide. Nanotechnology has proven highly
advanced science and promises easy delivery of targeted drugs to the brain. However, more
knowledge about its properties and features is needed to evaluate its dynamic behavior in
biomedical science. Recognizing the appropriate ligand and their incorporation on the
nanocarrier surface with optimum density is also of immense importance and has been
examined thoroughly. Antibody-mediated delivery of drugs beyond BBB might intrigue
researchers and should be explored meticulously in the future. Targeting specific brain
cells in different NDs must be called in question while developing a nanoformulation.
Analyzing toxicity studies and addressing safety issues of NPs is a must for all formu-
lation developments. Another major hurdle with the clinical translation of NPs is the difficulty
in study design, due to the difference in the ND biology studied in preclinical models and
clinical studies in humans. Restorative effect of nanomedi- cine on existing animal
models of different NDs, as reported by many, should be addressed with more clarity.
Multifunctional nanomaterials have been implemented for effective bioimaging,
diagnosis, and therapy of the neurodegenerative disorders.

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35. THANK YOU