NIOSOMES: A NOVEL DRUG DELIVERY SYSTEM

Presented by:

Sanjay Kumar Yadav

Enrollment No: A10647013015

Amity Institute of Pharmacy (AIP)

Introduction Factors Affecting Niosomes Preparation Methods of Preparation Characterization of Niosomes Stability of Niosomes Applications of Niosomes Toxicity of Niosomes

PRESENTATION FLOW

NOVEL DRUG DELIVERY SYSTEM (NDDS) Refers to approaches, formulations, technologies, and

systems for transporting a pharmaceutical compound in the body as needed to safely achieve its desired therapeutic effect

May involve scientific site-targeting within the body, or facilitating systemic pharmacokinetics

Technologies modify drug release profile, absorption, distribution and elimination for the benefit of Improving product efficacy and safety Patient convenience and compliance

INTRODUCTION

EXAMPLES OF NDDS • Niosomes • Liposomes• Nanoparticles • Resealed erythrocytes • Microspheres• Monoclonal antibodies • Micro emulsions• Antibody-loaded drug

delivery• Magnetic microcapsules• Implantable pumps

Figure 1: various drug delivery systems (Aitha S, 2013)

Novel drug delivery system, in which the medication is encapsulated in a vesicle which is composed of a bilayer of non-ionic surface active agents (Nasir A, 2012)

Are very small, and microscopic in size.

Although structurally similar to liposomes, they offer several advantages over them.

NIOSOMES

Figure 2: Niosomes Vesicles (Aitha S, 2013)

The vesicles forming amphiphile is a non-ionic surfactant stabilized by addition of cholesterol and small amount of anionic surfactant such as dicetyl phosphate

NIOSOMES

Figure 3: Vesicle of niosome (Aitha S, 2013)

Figure 4: Structure of Niosomes

STRUCTURE OF NIOSOMES

similar to liposomes, in that they are also made up of a bilayer.

However, the bilayer in the case of Niosomes is made up of non-ionic surface active agents rather than phospholipids.

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.

(Patel SM et al, 2012)

(Makeshwar KB, 2013)

STRUCTURE OF NIOSOMES

vesicle holds hydrophilic drugs within the space enclosed in the vesicle, while hydrophobic drugs are embedded within the bilayer itself.

Niosomes vesicle would consist of a vesicle forming amphiphile i.e. a non-ionic surfactant such as Span- 60, which is usually stabilized by the addition of cholesterol

(Makeshwar KB, 2013)

Figure 5: Structure of niosome (Makeshwar KB, 2013)

Entrap solutes in a manner analogous to liposomes. Osmotically active and stable. Accommodate the drug molecules with a wide range of

solubility. Exhibits flexibility in their structural characteristics

(composition, fluidity and size) Performance of the drug molecules is increased. Better availability to the particular site by protecting the

drug from biological environment. Surfactants used in preparation are biodegradable,

biocompatible and non-immunogenic

SALIENT FEATURES OF NIOSOMES(Makeshwar KB, 2013)

Improve the therapeutic performance of the drug molecules by Delayed clearance from the circulation Protecting the drug from biological environment Restricting effects to target cells

Niosomal dispersion in an aqueous phase can be emulsified in a nonaqueous phase to Regulate the delivery rate of drug Administer normal vesicle in external non-aqueous phase.

Handling and storage of surfactants requires no special conditions. Bioavailability of poorly absorbed drugs is increased. Targeted to the site of action by oral, parenteral as well as topical

routes.

ADVANTAGES OF NIOSOMES DELIVERY SYSTEM

(Makeshwar KB, 2013)

According to the nature of lamellarity

1. Multilamellar vesicles (MLV) 1-5 μm in size.

2. Large Unilamellar vesicles (LUV) 0.1 – 1μm in size

3. Small Unilamellar vesicles (SUV) 25 – 500 nm in size. According to the size

1. Small Niosomes (100 nm – 200 nm)

2. Large Niosomes (800 nm – 900 nm)

3. Big Niosomes (2 μm – 4 μm)

TYPES OF NIOSOMES

FACTORS AFFECTING THE FORMATION OF NIOSOMES

Type of surfactant influences encapsulation efficiency, toxicity, and stability of Niosomes

Mean size of Niosomes increases proportionally with increase in the HLB of surfactants

NATURE OF SURFACTANT

The surfactant/lipid ratio is generally 10-30 mM (1-2.5% w/w)

Increasing the surfactant/lipid level increases the total amount of drug encapsulated

SURFACTANT AND LIPID LEVELS

NATURE OF THE DRUG

The Physio-chemical properties of encapsulated drug influence charge and rigidity of the Niosome bilayer.

The drug interacts with surfactant head groups and develops the charge that creates mutual repulsion between surfactant bilayers, and hence increases vesicle size.

The aggregation of vesicles is prevented due to the charge development on bilayer.

Table 1: Effect of the nature of drug on formation vesicle (Kazi KM et al, 2010)

CHOLESTEROL(Tamizharas S et al, 2009)

Addition of cholesterol molecule to Niosomal system • Makes the membrane rigid • Reduces leakage of drug from the Niosome• Increases the chain order of bilayer• Strengthen the non‑polar tail of the non‑ionic

surfactant• Increase in the entrapment efficiency• Leads to the transition from the gel state to

liquid phase in Niosomes systems

MEMBRANE ADDITIVES

Cholesterol

Charge inducers are one of the membrane additives which are often included in Niosomes because

Increase surface charge density Prevent vesicles flocculation, Aggregation and

Fusion.

Examples: Dicetyl phosphate (DCP) and Stearyl amine (SA)

MEMBRANE ADDITIVES(Nasir A, 2012)

Film Method Ether Injection Method Sonication Reverse Phase Evaporation Heating Method Microfluidization Multiple Membrane Extrusion Method Transmembrane pH gradient (inside acidic) Drug

Uptake Process (remote Loading) The “Bubble” Method Formation of Niosomes from Proniosomes

METHODS OF PREPARATION (Madhav NVS, 2011)

• Mixture of Surfactant and Cholesterol

Dissolved in an organic solvent in a round-bottomed flask. (e.g. diethyl ether, chloroform,

etc.)

FILM METHOD • Also known as hand shaking

method

FILM METHOD

Figure 6: Steps of Film method (Madhav NVS, 2011)

A solution of the surfactant is made by dissolving it in

diethyl ether.

This solution is then introduced using an injection (14 gauge needle) into warm water or

aqueous media containing the drug maintained at 60°C.

Vaporization of the ether leads to the formation of single layered vesicles.

ETHER INJECTION METHOD

Figure 7: Steps of Ether injection method (Madhav NVS, 2011)

The mixture is probe sonicated

at 60°C for 3 minutes using a sonicator with a titanium probe

to yield Niosomes.

Added to the surfactant/ cholesterol mixture in a 10 ml glass

vial

Aliquot of drug solution in buffer

SONICATION

Figure 8: Sonication method (Madhav NVS, 2011)

Creation of a solution of cholesterol and

surfactant (1:1 ratio) in a mixture of ether

and chloroform

An aqueous phase containing the drug

to be loaded is added to this

Resulting two phases are

sonicated at 4-5°C

A clear gel is formed which is further sonicated

after the addition of phosphate buffered

saline (PBS)

Temperature is raised to 40°C and pressure is reduced

to remove the organic phase

Viscous Niosome suspension is formed which can be diluted with PBS and heated

on a water bath at 60°C for 10 minutes to yield Niosomes

REVERSE PHASE EVAPORATION

Non-toxic, Scalable and one-step method.

HEATING METHOD

Mixtures of non-ionic surfactant, cholesterol and/or charge inducing molecules are added to an aqueous medium e.g. buffer, distilled H2O, etc• In the presence of a Polyol such as glycerol.

Recent technique used to prepare Unilamellar vesicles of defined size distribution.

based on submerged jet principle

MICROFLUIDIZATION

Two fluidized streams interact at ultra high

velocities, in precisely defined micro channels within the interaction

chamber

The impingement of thin liquid sheet along

a common front is arranged such that the energy supplied to the system remains within the area of Niosomes

formation

The result is a greater uniformity,

smaller size and better reproducibility

of Niosome are formed

MICROFLUIDIZATION

Figure 9: Steps of microfludization method (Madhav NVS, 2011)

Good method for controlling Niosomes size.

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

Resultant suspension is extruded through polycarbonate membranes which are placed in series for upto 8

passages

Figure 10: Multiple membrane extrusion method (Madhav NVS, 2011)

Solution of surfactant and cholesterol is made

in chloroform

Solvent is then evaporated under reduced pressure to get a thin film on the wall of the round bottom flask, similar to the hand shaking

method

This film is then hydrated using citric

acid solution by vortex mixing

Resulting Multilamellar vesicles are then treated

to three freeze thaw cycles and sonicated

To the Niosomal suspension, aqueous solution containing 10mg/ml of drug is added

and vortexed

pH of the sample is then raised to 7.0-7.2 using

1M disodium phosphate

Mixture is heated at 60°C for 10 minutes

to give Niosomes

TRANSMEMBRANE pH GRADIENT DRUG UPTAKE PROCESS

A recently developed technique which allows the preparation of Niosomes without the use of organic solvents.

BUBBLE METHOD

Water-cooled reflux and thermometer is positioned in the first and second neck, while the third neck is used to supply nitrogen.

This dispersion is mixed for a period of 15 seconds with high shear homogenizer and immediately afterwards, it is bubbled at 70°C using the nitrogen gas to yield Niosomes.

FORMATION OF NIOSOMES FROM PRONIOSOMES (Makeshwar

KB, 2013)

Water soluble carrier such as sorbitol is coated with surfactant.

This preparation is termed “Proniosomes”.

T=Temperature.Tm = mean phase transition temperature

POST-PREPARATION PROCESSES

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 from unentrapped drug.

POST-PREPARATION PROCESSES (Makeshwar KB, 2013)

a) Size, Shape and Morphology

b) Entrapment efficiency

c) Vesicle diameter

d) In vitro release

e) Vesicle charge

f) Bilayer rigidity and Homogeneity

g) Osmotic Shrinkage

h) Physical stability of vesicles at different temperature

i) Turbidity Measurement

CHARACTERIZATION OF NIOSOMES

Structure of surfactant based vesicles has been visualized and established using freeze fracture microscopy

Photon correlation spectroscopy used to determine mean diameter of the vesicles.

Electron microscopy used for morphological studies of vesicles

Laser beam is generally used to determine size distribution, mean surface diameter and mass distribution of Niosomes.

SIZE, SHAPE AND MORPHOLOGY

After preparing Niosomal dispersion, unentrapped drug is separated by

Dialysis Centrifugation Gel filtration

Drug remained entrapped in Niosomes is determined by complete vesicle disruption using 50% n-propanol or 0.1% Triton X-100 and analysing the resultant solution by appropriate assay method for the drug. (Bragagnia M, 2012)

ENTRAPMENT EFFICIENCY

To determine drug loading and encapsulation efficiency, the niosomal aqueous suspension was ultracentrifuged, supernatant was removed and sediment was washed twice with distilled water in order to remove the adsorbed drug.

The Niosomal recovery was calculated as:

NIOSOMAL DRUG LOADING

(Makeshwar KB, 2013)

Niosomes diameter can be determined using Light microscopy Photon correlation microscopy Freeze fracture electron microscopy. Freeze thawing

VESICLE DIAMETER (Shirsand SB, 2012)

Figure 11: Microphotograph of niosomes (Shrisand SB, 2012)

IN VITRO RELEASE (Makeshwar KB, 2013)

The vesicle surface charge can play an important role in the behaviour of Niosomes in vitro and in vivo.

Charged Niosomes are more stable against aggregation and fusion than uncharged vesicles.

In order to obtain an estimate of the surface potential, the zeta potential of individual Niosomes can be measured by Microelectrophoresis, Fluorophores, and Dynamic light scattering.

Zeta potential is calculated by using Henry equation (S P Vyas, 2011)

Where is Zeta potential, is electrophoretic mobility, is viscosity of the medium and is dielectric constant

VESICLE CHARGE

(Makeshwar KB, 2013)

The biodistribution and biodegradation of Niosomes are influenced by rigidity of the bilayer.

Homogeneity can occur both within Niosomes structures themselves and between Niosomes in dispersion and could be identified via. NMR, Differential Scanning Calorimetry (DSC) and Fourier transform-infra red spectroscopy (FT-IR) techniques.

Membrane rigidity can be measured by means of mobility of fluorescence probe as a function of temperature. (Patel SM et al, 2012)

BILAYER RIGIDITY AND HOMOGENEITY

Osmotic shrinkage of vesicles can be determined by monitoring reductions in vesicle diameter, initiated by addition of hypertonic salt solution to suspension of Niosomes.

Niosomes prepared from pure surfactant are osmotically more sensitive in contrast to vesicles containing cholesterol.

OSMOTIC SHRINKAGE

Aggregation or fusion of vesicles as a function of temperature was determined as the changes in vesicle diameter by laser light scattering method.

The vesicles were stored in glass vials at room temperature or kept in refrigerator (4oC) for 3 months.

The changes in morphology of Multilamellar vesicles (MLVs) and also the constituent separation were assessed by an optical microscope.

The retention of entrapped drug were measured 72 hours after preparation and after 1, 2 or 3 months in same formulations

PHYSICAL STABILITY OF VESICLES AT DIFFERENT TEMPERATURE

Niosomes were diluted with bidistilled water to give a total lipid concentration of 0.312 mM

After rapid mixing by sonication for 5 min Turbidity was measured as the absorbance with an

ultraviolet-visible diode array spectrophotometer.

TURBIDITY MEASUREMENT

Vesicles are stabilized based upon formation of 4 different forces:

1. Van der Waals forces among surfactant molecules 2. Repulsive forces emerging from the electrostatic

interactions among charged groups of surfactant molecules

3. Entropic repulsive forces of the head groups of surfactants

4. Short-acting repulsive forces.

STABILITY OF NIOSOMES

FACTORS

Nature of surfactant

Structure of

surfactant

Temperature of

hydration

Nature of encapsulat

ed drug

Inclusion of a

charged molecule

FACTORS AFFECTING STABILITY OF NIOSOMES

A surfactant used for preparation of Niosomes must have a hydrophilic head and hydrophobic tail.

The hydrophobic tail may consist of one or two alkyl or perfluoroalkyl groups or in some cases a single steroidal group.

The ether type surfactants with single chain alkyl as hydrophobic tail is more toxic than corresponding dialkylether chain.

The ester type surfactants are chemically less stable than ether type surfactants and the former is less toxic than the latter due to ester-linked surfactant degraded by esterases to triglycerides and fatty acid in vivo.

The surfactants with alkyl chain length from C12-C18 are suitable for preparation of Niosome.

NATURE OF SURFACTANT (Singh CH, 2011)

The geometry of vesicle to be formed from surfactants is affected by its structure, which is related to critical packing parameters

Critical packing parameters can be defined using following equation,

Where

v = hydrophobic group volume,

lc = the critical hydrophobic group length

a0 = the area of hydrophilic head group

From the critical packing parameter value type of miceller structure formed can be ascertained as given below,

If CPP < ½ then formation of spherical micelles, If ½ < CPP < 1 formation of bilayer micelles, If CPP > 1 formation inverted micelles23.

surfactants with longer alkyl chains generally give larger vesicles

STRUCTURE OF SURFACTANT

(Madhav NVS, 2011)

The physico-chemical properties of encapsulated drug influence charge and rigidity of the Niosome bilayer.

The drug interacts with surfactant head groups and develops the charge that creates mutual repulsion between surfactant bilayers and hence increases vesicle size.

NATURE OF ENCAPSULATED DRUG (Singh CH, 2011)

Hydration temperature influences the shape and size of the Niosome.

For ideal condition it should be above the gel to liquid phase transition temperature of system.

Temperature change of Niosomal system affects assembly of surfactants into vesicles and also induces vesicle shape transformation

TEMPERATURE OF HYDRATION (Madhav NVS, 2011)

Niosomes as Drug Carriers Diagnostic imaging with Niosomes Drug Targeting

Delivery to the brain Anti cancer drugs Anti infectives

Targeting of bioactive agents To Reticulo-endothelial system (RES) To organs other than RES

NIOSOME DELIVERY APPLICATIONS (Malhotra M et al, 1994)

Ophthalmic drug delivery Delivery of peptide drugs Immunological application of Niosomes Transdermal delivery of drugs by Niosomes Delivery system for the vasoactive intestinal peptide

(VIP) Niosomes as carriers for Hemoglobin Niosomal vaccines

NIOSOME DELIVERY APPLICATIONS

Sustained Release Localized Drug Action

OTHER APPLICATIONS

Unfortunately, there is not enough research conducted to investigate toxicity of Niosomes.

It was determined that the ester type surfactants are less toxic than ether type surfactants.

In general, the physical form of Niosomes did not influence their toxicity as evident in a study comparing the formulations prepared in the form of liquid crystals and gels.

Nasal applications of these formulations caused toxicity in the case of liquid crystal type Niosomes.

TOXICITY OF NIOSOMES

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REFERENCE

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