The detail presentation about Lipid Polymer Hybrid Nanoparticles (LPHNPs)

1. 1
Krishna S. Jadhav
Department of Pharmaceutics
NATIONAL INSTITUTE OF PHARMACEUTICAL EDUCATION AND RESEARCH
LIPID POLYMER HYBRID NANOPARTICLES
(LPHNPs)

2. Flow of presentation
Introduction
Characteristic of LPHNPs
Types of LPHNPs
Composition of LPHNPs
Method of preparation
Characterization of LPHNPs
Recent advancements in LPHNPs preparation
Application of LPHNPs
Summary 2

3. POLYMERIC NANOPARTICLES
 Core shell structured nanoparticles to encapsulate a wide variety of therapeutic agents
 The use of amphiphilic polymers results in formation of nanoparticles with a hydrophobic
core and a hydrophilic shell
 Polymeric nanoparticles can be prepared from both natural polymers (e.g., chitosan) and
synthetic biodegradable and biocompatible polymers (e.g., poly-lactic-co-glycolic acid
(PLGA)).
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Advantages
•High structural integrity
Stability during storage
Long systemic circulation half life
Controlled release capability
easy to prepare and readily
functionalized for active targeted
delivery
Disadvantages
•Less biocompatible as
compared to liposomes

4. LIPOSOMES….
 Liposomes are simple microscopic vesicles in which an aqueous volume is entirely enclosed by a membrane
composed of lipid molecule
 liposomes have long been perceived as the more ideal drug delivery vehicles because of their superior
biocompatibility as liposomes are basically analogues of biological membranes, which can be prepared from
both natural and synthetic phospholipids
Advantages
•Encapsulation of both
hydrophilic and lipophilic drug
Ease of surface modification
Long systemic circulation half
life
Favourable safety
Disadvantages
Lack of structural integrity
Content leakage
Instability during storage
Dose dumping

5. Cont…
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LIPID POLYMER HYBRID NANOPARTICLES
POLYMERIC
NANOPARTICLES
LIPOSOME

6. LIPID POLYMER HYBRID NANOPARTICLES
 Polymer–lipid hybrid nanoparticles (LPHNPs) are an emerging nanoparticle drug delivery system
made of polymers and lipids taking advantages of both materials
 LPHNPs are solid, submicron particles composed of at least two components: the polymer and the
lipid. Various bioactive molecules such as drugs, genes, proteins, and targeting ligands can be
entrapped, adsorbed, or covalently attached in the hybrid system
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7. Characteristic of LPHNPs
 High structural integrity, stability during storage, and controlled release capability attributed to the
polymer core
 High biocompatibility and bioavailability owed to the lipid and lipid–PEG layers
 In addition, the inner lipid layer also functions as a molecular fence that minimizes leakage of the
encapsulated content during the LPHNPs preparation
 Furthermore, the inner lipid layer slows down the polymer degradation rate of the LPHNPs product by
limiting inward water diffusion, hence enabling sustained release kinetics of the content
 Wide selections of biocompatible polymers and lipids and numerous polymer–lipid combinations
 Easy fabrication by a single-step method
 superior capability of co-encapsulating therapeutic and imaging agents of different properties
With such favourable characteristics, LPHNPs have rapidly evolved into a robust drug delivery platform
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The LPHNPs exhibit

8. APPLICATION OF LPHNPs
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 The amount of drug in the outer shell and on
the particle surface is released in the form of
a burst
 The chemical nature of the lipid is also
important because lipids which form highly
crystalline particles with a perfect lattice
(e.g. monoacid triglycerides) lead to drug
expulsion
 Inherent low drug incorporation rate
 Shows gelation tendency
 High water content
 PLNs show sustained drug release profile
 Drugs are incorporated into the polymeric
core with high loading yields
 Lipid monolayer at the interface of the
hydrophobic core and the hydrophilic shell
reduces water penetration
Disadvantages of SLNs Advantages of LPHNPs
ADVANTAGES OF LPHNPs OVER SOLID LIPID NANOPARTICLES

10. TYPES OF LPHNPs
LPHNPs
Monolithic or
Mixed lipid
polymer NPs
Biomimetic
LPH systems
Polymer-caged
liposomes
Core-shell
Polymer core–
lipid shell
Hollow core
lipid–polymer–
lipid systems
nanoparticles are coated
with RBC membrane
they are also known as
erythrocyte membrane-
camouflaged polymeric
nanoparticles
made up of polymeric
matrix in which the
lipid molecules are
dispersed throughout
When polymers are
anchored on the surface
of liposomes, polymer-
caged liposomes
are formed which are
more stable systems.
Such systems have a multi
layered structure comprising
of lipid-PEG and lipids in the
outermost layers which coats
the polymeric layer
surrounding a lipid layer with
inner most hollow core

11. Polymer core–lipid shell
 Various terms like lipid polymer particle assemblies, lipid coated NPs, polymer
supported lipid shells, lipoparticles and nano-cell have been synonymously used for
these supramolecular lipid coated polymeric structures
 The hybrid architecture made up of polymeric core and layers of lipid
 provide several advantages
• Adjustable particle size and drug release
• ease of loading multiple agents
• better loading efficiency
• serum stability
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12. COMPOSITION OF LPHNPS
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13. METHOD OF PREPARATION FOR LPHNPs
SYNTHESIS APPROACH
Two step process Single step process
Polymer core and lipid shell prepared
separately and then merged together
Hybrid nanoparticles are prepared through
single step
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14. 11
Overview of preparation procedure

15. 1. TWO STEP SYNTHESIS APPROACH
 The polymeric core and lipid shell are prepared separately using two independent processes; then the
two components are combined by direct hydration, sonication, or extrusion to obtain the desired lipid
shell–polymer core structure
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A. Conventional two-step method

16. STEP 1:
 Preparation of polymeric nanoparticles
 PNPs are prepared by emulsification solvent evaporation (EME), Nano-precipitation or
high pressure homogenization
STEP 2:
 Preparation of lipid vesicles. The lipid component can be prepared in the form of a thin
dried film. Lipid is first dissolved in an organic solvent, like chloroform. Subsequently it is
subjected to rotary evaporation.
 The next step is the hydration of this dried lipid film by solution of polymeric NPs
 Lipid vesicles prepared by above mentioned method will be exposed to different mixing
protocols as given below
 Vortexing: It is a low energy mixing process.
 Ultra sonication 16

17. B. Non-conventional two-step method
 polymeric nanoparticles (i.e., polyglutamic acid) (400–500 nm) were prepared by spray drying after
which they were dispersed in dichloromethane solution containing the lipids (i.e., tripalmitin,cetyl
alcohol)
 The lipid–polymer suspension was later spray-dried to produce lipid-coated polymeric nanoparticles
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Spray drying
Soft lithography particle molding technique
Particle Replication in Non-Wetting Templates (PRINT) was employed to prepare LPHNPs
for gene delivery

18. PRINT technology (Particle Replication in Non-Wetting Templates )
Polymer was dissolved in
an organic solvent (e.g
DMSO with the genetic
material (i.e siRNA)
Cast onto a polyethylene
terephthalate (PET) sheet
The PET sheet was then
heated while in conformal
contact with a PRINT
mold containing 80 * 320
nm patterns
allowing the polymer to
flow into the mold and to
solidify to ambient
temperature, thereby
forming the Polymer
nanoparticles
the nanoparticles were
harvested from the mold
by
having the mold in
conformal contact with a
poly(vinyl alcohol)(PVA)-
coated PET sheet
The nanoparticles were
then released from the
PVA-coated PET sheet
using aqueous solution of
the lipids (i.e DOTAP,
DOPE)
Freeze dried-needle
shaped
LPHNPs with length of
~200 nm
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which dissolved the PVA layer, hence removing the
nanoparticles from the mold, and simultaneously forming
lipid-coated PLGA nanoparticles

19. PRINT technology (Particle Replication in Non-Wetting Templates )
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20. Governing formulation parameters in the two-step method
size homogeneity of the preformed lipid vesicles
 preformed vesicles prepared by extrusion were smaller and more uniform in size compared to vesicles
formed by thin lipid film hydration
Lipid formulation charge
 the monodispersity of the formed LPNs also depended on the charge of the lipid vesicles
 Minimal LPNs aggregation (i.e., narrow size distribution and high colloidal stability) was achieved by using
only one lipid type to form vesicles
lipid vesicle-to-polymeric nanoparticle ratio
 vesicle to nanoparticle ratio (AV/AP) significantly influenced the LPNs’ colloidal stability
 At high AV/AP and high DPTAP fractions-lipid vesicles acted as electrostatic stabilizers
 At low AV/AP and low DPTAP fractions-Incomplete lipid coating of the nanoparticle core of one LPN led to the exposure
of its anionic surface to the cationic DPTAP of another LPN
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AV/AP, and ionic strength of the continuous phase significantly
influence the resultant LPHNPs’ colloidal stability, and
consequently the size

21. 2. ONE STEP SYNTHESIS APPROACH
POLYMER LIPID HYBRID NANOPARTICLES
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the stabilizing agents used, where the lipid functions as stabilizers of the LPNs produced, in place of the
ionic/non-ionic surfactants (e.g., PVA, Poloxamer) typically used in the non-hybrid polymeric nanoparticle
preparation
Lipid and lipid PEG conjugate self assemble on polymer nanoparticles
Polymer solution is added to lipid aqueous solution drop-wise so
polymer precipitate out
Lipid and lipid PEG conjugates in aqueous solution and co-solvent can
be added
Free polymer and hydrophobic drug in water miscible organic solvent
lipid monolayer is formed
hydrophobic tail of lipids- polymer core
hydrophilic head sticks -external aqueous
surrounding
resulting in the formation of LPNs that are stabilized by the
lipid.
One-step method by nanoprecipitation
Sonication

22. One-step method by emulsification–solvent–evaporation (ESE)
 A single ESE method is employed when the substance to be encapsulated is soluble in a water-
immiscible solvent (i.e., oil phase)
 the oil phase, which contains the polymer and the substance to be encapsulated, is added, under
constant stirring or ultrasonication, into an aqueous phase containing the lipid to form an oil-in-water
(o/w) emulsion.
 When the oil phase is removed by evaporation, the polymer core is formed and simultaneously
 the lipid self-assembles around the polymer– thus essentially forming the LPNs
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ESE method
typically produces
larger LPNs
compared to the
nanoprecipitation
Single emulsification

23.  employed when the substance to be encapsulated is insoluble in any organic solvents, such that it
cannot be dissolved together with the polymer
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w/o emulsionw/o/w emulsion
evaporation of the oil phase,
gives rise to the LPNs
Double emulsification

24. RECENT ADVANCES IN ONE STEP METHOD OF NANO-PRECIPITATION
24(A) microfluidic nanoprecipitation to improve the LPHNPs size homogeneity
(B) multi-inlet vortex microreactor for high-throughput production of LPNs

25. FORMULATION PARAMETERS TO BE CONTROLLED
Lipid to Polymer Mass Ratio L/P Ratio
 Higher L/P ratios led to concentrations higher than the critical micelle concentration resulting in the formation of
liposomes in addition to the LPNs, whereas lower L/P ratios led to LPNs aggregation due to insufficient lipid coating
 The L/P ratio was also found to indirectly influence the encapsulation efficiency, loading, and release kinetics of the
encapsulated substance through its influence on the extent of the lipid coating of the polymer core
Lipid Coating
 it acts as a molecular barrier that keeps the encapsulated substance inside the polymer core during the self-assembly
process results in High EE
 lipid coating slows down the drug release kinetics by keeping the dissolution fluid medium away from the core
Lipid-PEG Fraction
 Increasing the lipid PEG fraction resulted in more stable LPNs,
Type of Lipid
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26. CHARACTERIZATION OF LPHNPs
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Parameter Method of characterization
Physicochemical Properties
Particle size, PSD, Zeta Potential DLS (Zeta sizer), Photon correlation
spectroscopy(PCS) (10-150 nm)
Morphology SEM, TEM, CSLM, fluorescence microscopy
Drug loading
and entrapment
HPLC, dialysis , centrifugation, membrane filtration
Drug release
Stability study
In vivo evaluation

27. SURFACE FUNCTIONALISATION OF LPHNPs
PEG layer is essential to maintain stability of the hybrid nanoparticles :
 In vitro by reducing nanoparticle aggregation
 In vivo by allowing the particles to evade recognition by the reticuloendothelial system (RES)
and other immune cells
 PEG molecules also provide functional groups for further modification of the hybrid nanoparticles
with targeting ligands for cell or tissue specific drug delivery
Targeting
ligands
Monoclonal
antibodies
Antibody
fragments
Aptamers Peptides Folic acid
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28. RECENT ADVANCEMENT IN LPHNPs
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29. APPLICATION OF LPHNPs
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Gene
Delivery
Diagnostic
Delivery
Drug
Delivery
• Hydrophobic Drug
• Hydrophilic Drug
• Co-delivery of
drug/nucleic acid
• Diagnostic agents
Contrast or Imaging agents
DNA, mRNA, small
oligonucleotides
(siRNA/miRNA

30. Case study
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32. SUMMARY
 PLN system is a highly versatile drug delivery platform due to its diverse selection and combination of
polymer and lipid materials and highly modifiable nanostructure using these building blocks. Such
properties allow PLN to efficiently load single or multiple agents with vastly different physicochemical
properties
 Superior efficacy and minimum tissue toxicity of PLN in pre-clinical studies suggest great potential of
LPHNPs for cancer treatments
 Despite the great progress made on synthesis, characterization and applications of the hybrid
nanoparticles, we call attention to a few key unmet challenges in further developing this new
nanoparticle platform as a robust drug delivery
 The simplicity of the synthesis process, especially the one-step self-assembly process, dramatically
increases the likelihood of producing the lipid-polymer hybrid nanoparticles in a scalable and
economical manner.
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33. FUTURE DIRECTION
 the multifunctional LPHNP platform with simultaneous imaging and drug delivery characteristics
could have important applications in cancer chemotherapy and diagnosis. Additionally, motivated by
the promises of gene therapy, there is much interest in developing LPHNP-mediated nonviral gene
delivery vectors for different therapeutic applications
 recent developments in microfluidics and PRINT technology could increase the production scale of
LPHNPs in larger quantities with defined material characteristics
 Despite these advances in the development and application of LPHNPs this field of research is in its
infancy and there are several challenges that need to be overcome to meet clinical expectations
 We expect that LPHNPs will eventually replace current liposome and polymeric NP therapeutics
delivery systems
 Future understanding of mechanisms that govern molecular interactions of PLN components and the
biological barriers will be very useful in designing multifunctional PLN systems for cancer treatment.
 Clinical translation of PLN eventually for personalized nanomedicine could be distinctively possible.
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34. Number of LPHNPs publications indexed in the PubMed database
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