Niosomes are non-ionic surfactant vesicles that can encapsulate both hydrophilic and lipophilic drugs. They are similar to liposomes but are more stable and less expensive. Niosomes are microscopic lamellar structures composed of non-ionic surfactants and cholesterol. They can be unilamellar or multilamellar depending on the preparation method. Niosomes increase the bioavailability and delivery of drugs while reducing side effects and can be used for targeted drug delivery applications like cancer treatment.

2. INTRODUCTION
 Niosomes are non-ionic surfactant
vesicles obtained on hydration of synthetic
nonionic surfactants, with or without
incorporation of cholesterol or other lipids.
 They are vesicular systems similar to
liposomes that can be used as carriers of
hydrophilic and lipophilic drugs
It is less toxic and improves the
therapeutic index of drug by restricting its
action to target cells

3. Niosomes are a novel drug delivery system, in which the
medication is encapsulated in a vesicle.
The niosomes are very small, and microscopic in size. Their size
lies in the nanometric scale.
Niosomes are unilamellar or multilamellar vesicles.The vesicle
is composed of a bilayer of non-ionic surface active agents and
hence the name niosomes.
A diverse range of materials have been used to form niosomes
such as sucrose ester surfactants and polyoxyethylene alkyl
ether surfactants, alkyl ester, alkyl amides, fatty acids and amino
acid compound.

4. Structure of Niosomes
Niosomes are microscopic lamellar structures which are formed
on the admixture of non-ionic surfactant of the alkyl or dialkyl
polyglycerol ether class and cholesterol with subsequent
hydration in aqueous media.
The bilayer in the case of niosomes is made up of non-ionic
surface active agents rather than phospholipids as seen in the
case of liposomes.
Most surface active agents when immersed in water yield
micellar structures, however some surfactants can yield bilayer
vesicles which are niosomes.
Niosomes may be unilamellar or multilamellar depending on the
method used to prepare them.

5. The niosome is made of a surfactant bilayer with its
hydrophilic ends exposed on the outside and inside of the
vesicle, while the hydrophobic chains face each other within
the bilayer.
Hence, the vesicle holds hydrophilic drugs within the space
enclosed in the vesicle, while hydrophobic drugs are
embedded within the bilayer itself.

6. The figure below will give a better idea of what a
niosome looks like and where the drug is located within
the vesicle ,

7. Comparison of Niosomes v/s Liposomes
Liposomes Niosomes
1) They are expensive. 1) They are not expensive.
2) Ingredients like phospholipids are 2) Ingredients like Surfactant are
chemically unstable. chemically stable.
3)It require special storage and 3) Not require special storage and
handling . handling.
4) liposomes are made from neutral or 4) Niosomes are made of uncharged
charged double chained phospholipids. single-chain surfactant molecules.
5) liposomes increase the 5) Niosomes also increase the
bioavailability of the drug and reduce bioavailability of the drug and reduce
the clearance. the clearance.
Niosomes can also be used for targeted drug delivery, similar to liposomes.

8. Advantages of Niosomes
The vesicle suspension being water based offers greater patient
compliance over oil based systems
Since the structure of the niosome offers place to accommodate
hydrophilic, lipophilic as well as ampiphilic drug moieties, they
can be used for a variety of drugs.
The characteristics such as size, lamellarity etc. of the vesicle
can be varied depending on the requirement.
The vesicles can act as a depot to release the drug slowly and of
controlled release.
Other advantages of niosomes are:
They are osmotically active and stable.
They increase the stability of the entrapped drug
Handling and storage of surfactants do not require any special
conditions
Can increase the oral bioavailability of drugs

9. o Can enhance the skin penetration of drugs
o They can be used for oral, parenteral as well topical use
o The surfactants are biodegradable, biocompatible, and non-
immunogenic
o Improve the therapeutic performance of the drug by protecting it
from the biological environment and restricting effects to target
cells, thereby reducing the clearance of the drug.
o The niosomal dispersions in an aqueous phase can be emulsified in
a non-aqueous phase to control the release rate of the drug and
administer normal vesicles in external non-aqueous phase.
o High patient compliance in comparison with oily dosage forms.
o Accommodate drug molecules with a wide range of solubilities.
o Characteristics of the vesicle formulation are variable and
controllable
o Osmotically active and stable, as well as they increase the stability
of entrapped drug.
o Biodegradable, biocompatible and nonimmunogenic.

10. Method of Preparation
A. Ether injection method
• Introduce a solution of surfactant dissolved in
diethyl ether into warm water maintained at 60°C.
• Surfactant mixture in ether is injected through 14-
gauge needle into an aqueous solution of material.
B . Hand shaking method (Thin film hydration technique)
• Surfactant and cholesterol are dissolved in a volatile
organic solvent
• Organic solvent is removed at room temperature
using rotary evaporator leaving a thin layer of solid
mixture deposited on the wall of the flask
• Dried surfactant film can be rehydrated with
aqueous phase at 0-60°C with gentle agitation

11. C . Sonication
• Aliquot of drug solution in buffer is added to the
surfactant/cholesterol mixture in a 10-ml glass vial
• Mixture is probe sonicated at 60°C for 3 minutes
using a sonicator with a titanium probe to yield
niosomes.
D. Multiple membrane extrusion method
• Mixture of surfactant, cholesterol and dicetyl
phosphate in chloroform is made into thin film by
evaporation
• The film is hydrated with aqueous drug solution and
the resultant suspension extruded through
polycarbonate membranes

12. E. Reverse Phase Evaporation Technique
• Cholesterol and surfactant (1:1) are dissolved in a
mixture of ether and chloroform.
• An aqueous phase containing drug is added to this
and the resulting two phases are sonicated at 4-5°C.
• organic phase is removed at 40°C under low pressure
• The resulting viscous niosome suspension is diluted
with PBS and heated on a water bath at 60°C for 10
min to yield niosomes.
F. Aqueous Dispersion Method
• Microdispersion of aqs.media containing solute for
encapsulation
• Controlled temp. and agitation provides vesicles

13. Table 1: Drugs incorporated into niosomes by
various methods
Method of Drug incorporated
preparation
Ether Injection Sodium
stibogluconate
Doxorubicin
Hand Shaking Methotrexate
Doxorubicin
Sonication 9-desglycinamide
8-arginine
Vasopressin
Oestradiol

14. Separation of Unentrapped Drug
1. Dialysis
The aqueous niosomal dispersion is dialyzed in a
dialysis tubing against phosphate buffer or normal
saline or glucose solution.
2. Gel Filtration
The unentrapped drug is removed by gel filtration of
niosomal dispersion through a Sephadex-G-50 column
and elution with phosphate buffered saline or normal
saline.
3. Centrifugation
The niosomal suspension is centrifuged and the
supernatant is separated. The pellet is washed and
then resuspended to obtain a niosomal suspension free

15. Characterization of Niosomes
A. Entrapment Efficiency
• Entrapment efficiency = (Amount entrapped total
amount) x 100
B. Vesicle Morphology
• Light Microscopy
• Photon Correlation Microscopy
• Freeze Fracture Electron Microscopy
• Confocal laser scanning Microscopy
• SEM
• TEM
C. In-vitro release

16. Factors affecting vesicles size, entrapment
efficiency and release characteristics
Drug
Amount and type of surfactant
Cholesterol content
Methods of preparation

17. Marketed Products
Lancome has come out with a variety of anti-ageing
products which are based on niosome formulations.
L’Oreal is also conducting research on anti-ageing
cosmetic products.

18. Applications
1) Targeting of bioactive agents
a) To reticulo-endothelial system
b) To organs other than RES
2) Neoplasia
Doxorubicin Niosomal delivery of Doxorubicin to
mice bearing S-180 tumor increased their life span
and decreased the rate of proliferation of sarcoma
3) Leishmaniasis
4) Delivery of peptide drugs
Oral delivery of 9-desglycinamide, 8-arginine
vasopressin entrapped in niosomes increase
stability of peptide significantly.

19. 5) Immunological application of niosomes
enhance the antibody production in response to
bovine serum albumin
6) Niosomes as carriers for Hemoglobin
7) Transdermal delivery of drugs by niosomes
e.g. erythromycin

20. Conclusion
The concept of incorporating the drug into niosomes
for a better targeting of the drug at appropriate tissue
destination .
They presents a structure similar to liposome and
hence they can represent alternative vesicular
systems with respect to liposomes
Niosomes are thoughts to be better candidates drug
delivery as compared to liposomes due to various
factors like cost, stability etc. Various type of drug
deliveries can be possible using niosomes like
targeting, ophthalmic, topical, parentral, etc.

21. REFERENCES
Vyas S.P. , Khar R.K. ,Targeted & Controlled Drug
Delivery, Novel Carrier Systems, CBS Publication ,
2002 ,Page No.249-279
Malhotra M. and Jain N.K. Niosomes as Drug
Carriers. Indian Drugs 1994, Page No: 81-86.
Chandraprakash K.S., Udupa N., Umadevi P. and
Pillai G.K. Pharmacokinetic evaluation of surfactant
vesicles containing methotrexate in tumor bearing
mice. Int. J. Pharma. 1990; R1-R3: 61.
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