Upload
balaji-nakkala
View
512
Download
36
Tags:
Embed Size (px)
DESCRIPTION
contains information regarding niosomes as carrier in transdermal drug delivery
Citation preview
NIOSOMES AS CARRIER (IN TRANSDERMAL DRUG DELIVERY)
CONTENTS
•INTRODUCTION
•SALIENT FEATURES
•STRUCTURE OF NIOSOME
•COMPONENTS
•PREPARATION METHODS
•CHARACTERIZATION
•Role of NIOSOMES IN TRANSDERMAL DRUG DELIVERY
• PRODUCTS
•References
INTRODUCTION
Transdermal drug delivery is problematic as the skin acts as a natural
barrier.
Therefore several methods have been assessed to increase the rate.
One of the approaches is the use of niosomes.
Niosomes are microscopic lamellar structures formed on admixture of non-ionic
surfactant and cholesterol with subsequent hydration in aqueous media.
SALIENT FEATURES:
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
Can enhance the skin penetration of drugs
They can be used for oral, parenteral as well as topical use
contd.
SALIENT FEATURES
The surfactants are biodegradable, biocompatible, and non-immunogenic .
Improve the therapeutic performance of the drug by protecting it from the
biological environment and restricting effects to target cells.
STRUCTURE:
In the surfactant bilayer hydrophilic ends exposed
on the outside and inside of the vesicle, while the hydrophobic chains face
each
other within the bilayer.
The vesicle holds hydrophilic drugs within the space enclosed in the
vesicle, while hydrophobic drugs are embedded within the bilayer itself.
COMPONENTS:
The main components of niosomes are Non ionic surfactants Cholesterol Water Drug
The association of non-ionic surfactant monomers into vesicles on hydration is a result of the interfacial tension between water and the hydrocarbon portion of the amphiphile which causes these groups to associate. Simultaneously, the steric, hydrophilic and/or ionic repulsion between the head groups ensures that these groups are in contact with water.
These two opposing forces result in a molecular assembly.
Various non ionic surfactants used are
Sorbitan monostearate (span 60)Polyoxyethylene 2 stearylether (brij 72)Polyoxyethylene sorbitan monostearate (tween 61)Glyceryl monostearatePolyoxyethylene 4 laurylether (brij 30) Di glyceryl monolaurate Tetra glyceryl monolaurate
The mean size of niosomes increases regularly with increase in the HLB from Span 85(1.8) to span 20(8.6).
Vesicles obtained from the long alkyl chain (C18) surfactants give higher entrapment efficiency and were more stable than the shorter alkyl chain (C12) surfactants.
The effect of niosome forming surfactant
Increased hydrophilicity causes
Increased leakage of low molecular weight drugs from aqueous compartments.Decreased stability of niosome preparation Improved transdermal delivery of hydrophobic molecules.
Increased hydrophobicity causes
Decreased leakage of low molecular weight drugs from aqueous compartments.Increased encapsulationIncreased stability of niosome preparation Decreased toxicity
Cholesterol content Inclusion of cholesterol in niosomes increases its diameter and entrapment efficiency.
Presence of cholesterol in bilayer reduces permeability and improves retention of solute.
1:1 molar ratio of the surfactants to cholesterol is generally used.
PREPARATION METHODS
Ether injection method
Hand shaking method
Reverse phase evaporation technique
Trans membrane pH gradient Drug Uptake Process
The “Bubble” Method
Sonication
Micro fluidization
Multiple membrane extrusion method
Formation of niosomes from proniosomes
CHARACTERIZATION
Entrapment efficiency
Vesicle diameter
light microscopy,
photon correlation microscopy ,
freeze fracture electron microscopy.
In-vitro release
NIOSOMES IN TDDSDrug molecules in contact with the skin surface can penetrate by three potential pathways: • The sweat ducts • sebaceous glands• stratum corneum
Ideal properties of a molecule penetrating stratum corneum are.
Aqueous solubility > 1mg/mlLipophilicity 10 < Ko/w < 1000Molecular weight < 500 DaltonsMelting Point < 200ºCpH of saturated aqueous solution pH 5-9
MECHANISMS
Several mechanisms of niosomes to modulate drug transfer across skin are
Adsorption and fusion of niosomes onto the surface of skin.
The vesicles act as penetration enhancers to reduce the barrier properties of the stratum corneum.
The lipid bilayers of niosomes act as a rate-limiting membrane.
Niosomal products in TDDS areFlurbiprofen PiroxicamEstradiolLevonorgestrolNimesulideDithranolKetoconazoleEnoxacinKetorolac
REFERENCES
1. Ijeoma F. Uchegbu a, Suresh P. Vyas, Non-ionic surfactant based vesicles (niosomes) in drug delivery , International Journal of Pharmaceutics 172 (1998) 33–70.
2. Gregor Cevc, Lipid vesicles and other colloids as drug carriers on the skin, Advanced Drug Delivery Reviews 56 (2004) 675– 711.
3. Maria Manconi, Chiara Sinico, Donatella Valenti, Francesco Lai, Anna M. Fadda, Niosomes as carriers for tretinoin III. A study into the in vitro cutaneous delivery of vesicle-incorporated tretinoin, International Journal of Pharmaceutics 311 (2006) 11–19
4. RAJNISH ARORA, AND C. P. JAIN, ADVANCES IN NIOSOME AS A DRUG CARRIER, Asian journal of pharmaceutics,vol1,issue 1,2007.
5. Alok namedo,n.k.jain,niosomes as drug carrier,Indian J.pharm. Sci., 1996,58(2),41-46.6. www.pharmainfo.net
THANK YOU