Niosomes are used in studies for drug delivery or gene transfer. However, their physical properties and features relative to liposomes are not well documented. To characterize and more rationally optimize niosome formulations, the properties of these vesicle systems are compared to those of liposomes composed of phosphatidylcholine and phosphatidylethanolamine lipids plus cholesterol. Niosomes are highly stable and only slightly more leaky than liposomes as assayed by calcein leakage; the permeability for ions (KCl) is higher than that of liposomes. Contrary to liposomes, the size of niosomes decreases substantially upon freezing in liquid nitrogen and subsequent thawing, as shown by cryo-EM and dynamic light scattering. The packing of niosomal membranes was determined by laurdan fluorescence and is slightly lower than that of liposomes. We did not succeed in the functional reconstitution of the L-arginine/L-ornithine antiporter ArcD2 in niosomes, which we attribute to the non-ionic nature of the surfactants. The antimicrobial peptides alamethicin and melittin act similarly on niosomes and liposomes composed of unsaturated components, whereas both niosomes and liposomes are unaffected when saturated amphiphiles are used. In conclusion, in terms of stability and permeability for drug-size molecules niosomes are comparable to liposomes and they may offer an excellent, inexpensive alternative for delivery purposes.

1. Niosome & Liposome
Faysal Ahmed
Id: 193-46-293

2. Defintion
Liposome:
A liposome is a spherical-shaped vesicle that is composed of one or more
phospholipid bilayers, which closely resembles the structure of cell membranes.
Niosome:
Niosomes are one of the promising drug carriers that have a bilayer structure and
are formed by self-association of nonionic surfactants and cholesterol in an aqueous
phase

3. Structures

4. Classifications
Niosome:
According to nature of Lamillarity:
1) Multicellular Vesicle- 1-5 µm in size
2) Large Unilamillar Vesicle- 0.1-1 µm in size
3) Small Unilamillar Vesicle- 25-500 nm in size
According to size:
1) Small niosome- 100-200 nm
2) Large niosome- 800-900 nm
3) Big niosome- 2 µm-4 µm

5. Classification
Liposome:
On the basis of their size and number of bilayers, liposomes can
also be classified into one of two categories:
(1) multilamellar vesicles (MLV)
(2) unilamellar vesicles.
Unilamellar vesicles can also be classified into two categories:
(1) large unilamellar vesicles (LUV)
(2) small unilamellar vesicles (SUV).

6. Niosome Method of Preparation
Niosome:
1. Formation of Niosome by the Proniosomes Method
2. Sonication
3. Micro Fluidization
4. Thin Film Hydration Method
5. Reverse Phase Evaporation

7. Liposome Method of Preparation
General Method of preparation of Liposome:
1. Drying down lipids from organic solvent.
2. Dispersing the lipid in aqueous media.
3. Purifying the resultant liposome.
4. Analyzing the final product.

8. Evaluation of Niosome & Liposome
Niosome:
1) Entrapment Efficiency
2) Vesicle diameter
3) In-Vitro release method
Liposome:
1) Particle size determination
2) Drug entrapment efficiency
3) In- Vitro release study
4) Zeta Potential

9. Applications
Niosome:
Gene delivery
Drug targeting
Delivery of peptide drugs
Studying immune
Response
Carriers for haemoglobin
Transdermal drug delivery systems
Cosmetics

10. Applications
Liposome:
In gene delivery
Enzyme replacement therapy
As drug delivery carriers
Anti microbial therapy
In multi drug resistance
In tumor therapy
In immunology
In cosmetology