The size of the market for delivery of liposome-based medicines depends on the growing prevalence of chronic diseases and the growing demand for non-invasive drug distribution solutions.In 2019; the liposomal doxorubicin sector accounted for around 36.22 percent of the market.In 2021, the cancer therapy segment represented the greatest share of the market in terms of application. The market is estimated to grow at a CAGR of 8.8% from 2020 to 2027.

1. Vinayshri S. Salunkhe
LIPOSOMES: A DRUG DELIVERY SYSTEM
Presented By- Under The Guidance of:-
Ms. Vinayshri S. Salunkhe. Dr. H.S.Mahajan.
Roll No:- MPH-14 Dept. of Pharmaceutics
04-08-2021 1

2. Contents-
 Background
 Introduction
 Classification of liposomes
 Methods of preparation
 Interaction of liposomes with cells
 Application of liposomes
 Characterization of Liposomes
 Current liposomal drug preparation
 Conclusion
 References
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3. Global Liposome Drug Delivery Market: Introduction
The global liposome
drug delivery market was
valued at US$ 3.6
Bn in 2018
And it reach valuation of
~US$ 8 Bn By 2027
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https://www.transparencymarketresearch.com/liposome-drug-delivery-market.html

4. 04-08-2021 4

5. Introduction -
“Liposomes(Lipos-fat; Soma- body) are
concentric, self-closed[4], microscopic
vesicle in which an aqueous volume is
entirely enclosed by curved membranous
lipid bilayer[1] and the drug molecules can
either be encapsulated in aqueous space or
intercalated into the lipidic bilayers[2].”
-Carry both hydrophilic and lipophilic
molecules.
Fig.1 : General structure of liposome
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6. Components of liposome structure-
Phospholipids and cholesterol- main components.
• Phospholipids –
-Amphipathic and capable of forming bilayer
hence are integral part of liposomes [4].
-2 acyl chains linked to a head group by means of
glycerol-backbone[4].
-Most common phospholipid is
Phosphatidylcholine (PC). Known as
“lecithin”[2] .
-At various temperature it exist in different
phases.
Fig.2: Different regions of liposome
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7. • Cholesterol-
-Provide rigidity to fluid phase vesicle. It act as a “fluidity buffer” [3].
-Itself does not form bilayers, but it can be incorporated in 1:1 or 2:1
molar
ratio, can bring major changes in membrane[3].
-Increases the Tc of the membrane &
decreases the permeability of the bilayer[3] .
-Restrict the transformation of trans to gauche confirmation[3].
-Transition temperature of phospholipids(Tc) (Temperature at which all lipids
changes their fluidity)
- It determines fluidity and permeability of bilayer & influence the curvature of liposomes[5].
- Temp <TC lipids are gel [5].
- Temp >TC Lipids are in liquid-crystalline phase[5].
- Longer chain at higher TC
[5]
.
-Tc depends on length of fatty acid chain , their degree of saturation charge and head group
species[3].
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8. Classification of liposomes[3]-
Types
Based on structural parameter
Multilamellar large vesicles (>0.5 µm)
Oligolamellar vesicles (0.1-1 µm)
Unilamellar vesicles (all size range)
Small unilamellar vesicles (20-100nm)
Large unilamellar vesicles (>100nm)
Based on composition and application
Conventional liposomes(CL)
pH sensitive liposomes
Cationic liposomes
Long circulatory (stealth) liposomes(LCL)
Immuno-liposomes
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9. Conventional
Long circulating
Immuno
Cationic
Fig.3 Classification of liposomes
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10. Methods of Preparation[3] -
Methods of liposome preparations
Passive loading techniques Active loading techniques
Mechanical dispersion methods Solvent dispersion methods Detergent removal methods
• Liquid film hydration by
-Hand shaking,
-non-hand shaking
• Sonication
• French pressure cell
• Membrane extrusion
• Micro-emulsification
• Dried reconstituted vesicles
• Freeze-thawed liposomes
• Ethanol injection
• Ether injection
• Double emulsion vesicles
• Reverse phase evaporation
vesicles
• Detergent removal from mixed
micelles by
- Dialysis
- Column chromatography
- Detergent adsorption
using Bio-beads
Size
Reduction
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11. General method of liposome preparation [3]-
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Drying down lipid from organic
solvent
Dispersion of lipid in aqueous medium
Purification of resultant liposomes
Analysis of final product

12. 1.Mechanical dispersion method -
Lipid dissolve in organic
solvent/co-solvent
Remove organic solvent under
vacuum
Film deposition
Solid liquid mixture is hydrated by
using aqueous buffer
Lipid spontaneously swell &
Hydrated
Liposome formation
A) Lipid hydration method [2,3] -
Hand shaking method Non Hand shaking method
Dispersion of film by manual agitation Provide agitation by rotary flash
evaporator by exposing film to a steam
of nitrogen
Multilamellar Vesicles Large Unilamellar Vesicles
Encapsulation efficacy as high as 30% Encapsulation efficacy high
Passive loading technique [3]
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13. a)Sonication-
Size reduction of multilamellar vesicles[3]-
To convert large size into smaller homogeneous vesicles. Which includes following techniques but second
set of method to increase entrapment volume of hydrated lipids/to reduce lamellarity freeze-drying, freeze
thawing or introduction of vesiculation by ions or pH change[3].
MLV in test tube
Sonicate for 5-10 min above phase transition
temperature
Filter &centrifuge at 100000 rpm for 30min
at 20℃
Decant top layer
Sonicated unilamellar vesicles
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14. b) French Pressure Cell [3] –
- The extrusion of MLV at 20,000 psi at 4℃ through
a small orifice.
- Yields Uni- or oligo- lamellar vesicles (30-80 nm)
- Advantages over sonication method.
-More stable, less structural defect
-leakage of content is lower than sonication
c) Membrane extrusion [3]–
- Size of liposome reduced by passing them through
membrane filter.
- Much lower pressure (<100psi)
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15. B) Micro-emulsification [3] –
-Micro fluidizer pumps the fluid at high pressure (10,000psi,600-700bar) through a 5µm orifice.
-Negative lipids tends to decrease their size, increasing cholesterol concentration gives larger liposomes.
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16. D) Freeze-thawed liposomes[3] -
C) Dried-reconstituted Vesicles[3] -
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17. 2) Solvent dispersion methods [2,3] -
a) Ethanol injection-
-Alternative for preparation of SUV
without sonication.
- low risk of degradation of sensitive
material
b) Ether injection –
-It has little risk of causing oxidative
degradation
-careful control needed for introduction of
lipid solution
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17

18. c)Double emulsion
[3] –
Organic solution + Lipid
+ Aqueous phase
Emulsion(w/o)
Hot aqueous solution of buffer
Multi lamellar vesicle
w/o/w(double emulsion )
LUVs
d) Reverse phase evaporation(MLV,LUV) [3] -
Emulsion
Evaporation under reduced
pressure, rotary evaporator
Semi solid gel
Shake to get LUVs
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19. Dialysis Column chromatography
Detergent Adsorption using
Bio-beads-
3) Detergent depletion/solubilization method of passive loading [3,4]
• Detergent removed from
mixed micelle by dialysis,
which is facilitated by
using high CMC.
• Ex: Sodium cholate,
Sodium deoxycholate,
octyl glucoside.
• Removal of deoxycholate
by passing the dispersion
over Sepadex G-25
column pre-saturated
with constitutive lipids
and pre-equilibrated with
hydrating buffer.
• Removal of detergent
by using proper
adsorbent.
• Ex: Bio-beads SM-2
used to adsorb Triton X-
100.
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20. Active loading technique [3]
After drying in process
Film/cake of lipid is form
Swelling in fluid
Formation of liposomes
Loading of drug
on pH-
Gradient
technique
2 process which causes pH imbalance and active loading :
1. Vesicles are prepared in low pH solution, thus generating low pH
within the interiors.
2. Addition of base to extra liposomal medium.
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21. Mode of liposome/Cell interaction-
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22. Characterization of Liposomes[2,3,4] :
Parameters Techniques used
Shape, Lamellarity • Freeze-fracture and Freeze-etch electron microscopy[3]
• NMR[3]
• Atomic force microscopy[4]
Size and size distribution • Laser light scattering[2]
(Dynamic light scattering, turbidity measurement)
• TEM(Negative stain, Cryo-transmission) [3]
• SEM[3]
• Gel permeation [2,3]
Surface charge • Capillary zone electrophoresis[4]
• Zeta potential[3]
Encapsulation efficiency & Entrapped volume • Minicolumn centrifugation[3,4]
• Using Radioactive markers[3,4]
Gel filtration, Dialysis[4]
• Protamine aggregation[3,4]
Phase transition temperature • DSC[4] , NMR[4]
Release • Dialysis
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23. Recent liposomal drug preparations
Type of Agents Examples
Anticancer Drugs Daunorubicin(Dauno xome® ), Doxorubicin(Doxil®, Rubilong®),
Paclitaxel(Taxol®)
Anti bacterial Ampicillin(Amfight®), piperacillin, rifampicin
Vaccines Corona virus vaccine (Pfizer, Moderna)
Hepatitis A antigen(Epaxal-Berma vaccine®),
Influenza (Influsome-Vac®)
Rabies virus, Malaria merozoite, Malaria sporozoite,
Antiviral AZT (Retrovir®)
Fungicides Amphotericin-B(AmBisome®)
Enzymes Hexosaminidase A ,Glucocerebrosidase, Peroxidase
Pain Management Morphine(DepoDur®)
Gene therapy mRNA vaccine (Pfizer, Moderna)
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24. Liposomal preparation in current scenario -
1. Liposomal Amphotericin-B –: Black fungus infections.(~10lakh vial allocated across
the country).
2. mRNA vaccines of Moderna and Pfizer/BioNTech-: Corona virus infection
04-08-2021 24

25. Conclusion-
04-08-2021 25
Liposomes having multiple advantages which includes increased stability of
the encapsulated drug, reduced contact of sensitive tissues with therapeutic
molecules, decreased drug toxicity, improved pharmacokinetic and
pharmacodynamics properties, the ability to regulate the rate of drug release, and
the potential of their structure to accept the desired chemical modification.
 Hence, The demand of liposome within the global liposomes market is raised
on account of advancements in medical and pharmaceutical research.
So, by reviewing liposomes pros and cons, scientists will be able to improve
them in future research works and meet the global demand.

26. 1. Bangham A.D, Standish M.M. Watkins, J.C. “The First Description of Liposomes” J.
Mol. Biol., 13:238-252 (1965).
2. N.K. Jain, “Controlled and Novel Drug Delivery”, 1st ed.’ CBS Publishers and
Distributors, New Delhi (1997), pp. 305-344.
3. S.P. Vyas and R. K. Khar, “Targeted and Controlled Drug Delivery: A Novel Carrier
System”, 1st ed; CBS Publishers and Distributors, New Delhi (2002), pp. 173-243.
4. Dr. R. S. R. Murthy, “Vesicular and Particulate Drug Delivery System”, 1st ed; Career
Publications, Maharashtra (2010), pp. 5-73.
5. Higuera-Ciapara, Beltran-Gracia, E.,Lopez-Camacho,A., “Nanomedicine review:
clinical developments in liposomal applications”. Cancer Nano 10, 11 (2019).
6. Rommasi,F., Esfandiari, N. “Liposomal Nanomedicine: Applications for Drug Delivery
in Cancer Therapy”. Nanoscale Res Lett 16, 95 (2021).
References-
04-08-2021 26

27. 7. Yang Y, Yang X, Li H, Li C, Ding H, Zhang M, Guo Y, Sun M. Near-infrared
light triggered liposomes combining photodynamic and chemotherapy for
synergistic breast tumour therapy. Colloids Surf B Biointerfaces. (2019) Jan
1;173:564-570.
8. Abeyratne E, Tharmarajah K, Freitas JR, Mostafavi H, Mahalingam S, Zaid A,
Zaman M, Taylor A. Liposomal Delivery of the RNA Genome of a Live-
Attenuated Chikungunya Virus Vaccine Candidate Provides Local, but Not
Systemic Protection After One Dose. Front Immunol. (2020) Mar 5;11:304.
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