Explanation about the nanosystems used in Drug delivery

1. INTRODUCTION TO
NANOMEDICINE
NANOSYSTEMS
Vesicles
Liposomes
Polymeric micelles
Dendrimers
By
Girish Kumar K
IV MSc
Biomedical Science

2. Nanosystems
• Nanotechnology to deal with nanoscale
objects, has been developed at three major
levels Nanomaterials, Nanodevices and
NANOSYSTEMS
• Nanosystems has wide applications in
Engineering, Physical Science and
Bioscience.

3. VESICLES
• Drug delivery refers to approaches, formulations,
technologies and systems for transporting a
pharmaceutical compound in the body as needed to
safely achieve its desired therapeutic effect.
• Currently, vesicles as a carrier system have become
the vehicle of choice in drug delivery.
• Vesicular delivery system provides an efficient
method for delivery to the site of infection, leading to
reduce of drug toxicity with no adverse effects.
• Vesicular drug delivery reduces the cost of therapy by
improved bioavailability of medication, especially in
case of poorly soluble drugs.
• They can incorporate both by hydrophilic and liophilic
drug.

4. Different novel approaches used for delivering
the drugs by vesicular system include
LIPODIDAL BIOCARRIERS
Liposomes Ethosome Sphingosomes
Transferosomes Pharmacosomes Virosomes
Phytosome

5. NON-LIPOIDAL BIOCRRIERS
Niosomes Biolosomes
Aquasomes

6. Liposomes
• They are vesicles or bags in
which aqueous volume is
entirely closed by a
membrane composed of
lipid(fat) molecules, usually
phospholipids.
• They are bilayered vesicles
in which aqueous volume is
entirely enclosed by a
membranous lipid bilayer that
are mainly composed of
natural or synthetic
phospholipids.
• These vesicles can
encapsulate water soluble
drugs in their aqueous
spaces and lipid soluble drug

7. Mechanism of Liposome formation
• To understand why liposome are formed when
phospholipids are hydrated it is needed to
understand basic physiochemical features of
phospholipids.
• Phospholipids are amphipathic molecules which
have affinity for both aqueous and polar moieties
as they have hydrophobic tail and is composed of
two fatty acids containing 10-24 carbon atoms 0-
6 double bonds in each chain.
• In aqueous medium the phospholipid molecules
are oriented in such a way that the polar portion
of the molecule remains in contact with the polar
environment and at the same shield the non
polar part.

8. • They align themselves closely in planer
bilayer sheets to minimize the interaction
between the bulky aqueous phase and long
hydrocarbon fatty acyl chains.
• This alignment requires input of sufficient
amount of energy (shaking, sonication,
homogenization, heating etc.)
• Interactions are completely eliminated when
these sheets fold over themselves to form
closed, sealed and continuous bilayer
vesicles.

10. Classification
• Multilamellar vesicles (MLVs) – several
bilayers and size ranging from 100nm to
20m.
• Small unilamellar vesicles (SUVs) –
composed of single lipid bilayer with
diameter ranging from 20-100nm.
• Large unilamellar vesicles (LUVs) – consist
of single bilayer with diameter ranging from
0.1-1m.
• Multivesicular vesicles (MVVs) – consists of
vesicles with size ranging from 100nm-20m.

11. Therapeutic application
• Liposomes are used as drug/protein delivery
vehicles
• Enhances drug solubilisation
• Enzymal replacement therapy and lysosomal
storage disorder
• Used in antifungal, antiviral, antimicrobial
and tumour therapy.

12. Advantage
• Provide selective passage targeting to
tumour tissues.
• Increased efficacy and therapeutic index.
• Increased stability via encapsulation.
• Reduction in toxicity of encapsulated agent.
• Improved pharmacokinetic effect.
• Used as carrier for controlled and sustained
drug delivery.
• Can be made into variety of sizes.

13. Disadvantage
• Leakage of encapsulated drug during
storage.
• Uptake of liposomes by the
reticuloendothelial system.
• Batch to batch variation.
• Once administrated cannot be removed.

14. • Another type of drug delivery vehicle used
is polymeric micelles.
• These are spherical in shape and are
formed by single chain lipids.
• A micelle is aggregate of surfactant
molecules dispersed in a liquid colloidal.
• In a micelle, the hydrophobic tails of
several surfactant molecule assemble into
an oil-like core.
Polymeric micelles

15. Polymeric micelles
• Miceller systems for systemic delivery of
insoluble drugs.
• Amphiphilic copolymer self associate to form
micelles in water.
• Small size <100nm in diameter leads to
avoiding of renal excretion and RES.
• Small size also leads to increase endothelial
cell permeability.
• Accumulate gently into tumour cell than the
normal.

16. • Amphiphilic block copolymers that self
assemble to form a micelle with hydrophobic
core and a hydrophilic shell.
• The drugs can be attached to shell or
encapsulated within the core.

19. Advantage
• It can carry water insoluble drugs.
• It is biocompatible.
• It is biodegradable.
• Can be easily modified and functionalized.

20. Disadvantage
• It is more difficult to selectively target the
cancer cells.
• Optimal concentration must first be
determine for micelle form.

21. Dendrimers
Dendritic materials comprises sub classes
such as
• Dendrimers
• Dendron
• Hyperbranched polymers
• Dendrigraft polymers
• Dendronized polymers

22. • Dendrimers are polymer-based drug
delivery vehicles.
• They have a core that branches out in
regular intervals to form a spherical, small
and a very dense narrow carrier.
• Dendrimers are highly branched, three
dimensional feature the resembles architect
of a tree.
Dendrimers

23. • Two strategies are used for the application
of dendrimers to the drug delivery
1. Drug encapsulation by dendritic
structure
2. Drug conjugation to dendrimers
• Firstly, the drug molecules can be physically
entrapped inside the dendrimers.
• Secondly, the drug molecules can be
covalently attached onto surface or other
functional group.
• Various functional moieties based on
dendrimers provide miscellaneous
biomedical applications of these promising

26. There are different types of
Dendrimers
• Pamam dendrimers – Poly (amidoamine)
dendrimes posses amino groups on the
surface.
• Pamamos dendrimers – Inverted
unimolecular micelles consists of
hydrophilic nucleophilic PAMAM interiors
and hydrophobic organosillicon (OS)
exterior.
• PPI Dendrimers – Poly alkyl amines having
primary amines as end groups and its
interior consists of numerous tertiary
trispropylene amine.

27. Thank you