Metrics details. NET was prepared by film-ultrasonic dispersion method. The effects of emodin components at different ratios on encapsulation efficiency were investigated. The NET envelopment rate was determined by ultraviolet spectrophotometry. Sixty male SD rats were assigned to groups randomly.

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This article was designed to review all aspects of a novel class of vesicles, transfersomes. Tranfersomes and the fundamental concept of transfersomes were launched by Gregor Cevc in the year It exists as an ultra-deformable complex having a hydrated core surrounded by a complex layer of lipid. The carrier aggregate is composed of at least one amphipathic molecule like phospholipids which when added to aqueous systems self-assemble into a bilayer of lipid which eventually closes into a lipid vesicle and one bilayer softening agent which is generally a surfactant which is responsible for the flexibility of the vesicle.

Transfersomes provide the primary advantage of higher entrapment efficiency along with a depot formation which releases the contents slowly. The characterisation of transfersomes is similar to that of other vesicles like liposomes, niosomes and micelles. Transfersomes can be used for delivery of insulin, corticosteroids, proteins and peptides, interferons, anti-cancer drugs, anaesthetics, NSAIDs and herbal drugs.

Certain disadvantages associated with transfersomes including deformation by a highly hydrophobic drug can be overcome by preparing transethosomes having characteristics of both transfersomes and ethosomes and has a mechanism of action that is a fusion of the mechanism of action of both.

Deformability and penetration studies have proven that transethosomes provides a deeper penetration of the skin. Vesicular systems have gained immense importance in the last few years as a means for sustained and efficient drug delivery. Vesicular drug delivery is preferred over other formulations due their definite characteristics of a better capacity of encapsulating hydrophillic and hydrophobic drugs, no toxicity, biodegradability, increased time of drug presence in the circulation due to encapsulation in the vesicular structure, ability to target different organs and tissues and an increased bioavailability.

Table 1 highlights the advantages and disadvantages of the vesicular systems. The transdermal route for drug delivery is of great importance today because it overcomes the main problems associated with the oral drug delivery systems. There are many techniques which have come into light for enhancing the transdermal delivery including electrophoresis, iontophoresis, microneedles, nanoneedles, sonophoresis and vesicles like liposome, ethosome, transfersome and cetosomes.

Transfersomes provide a great scope for the delivery of active constituents. This carrier system is composed of phospholipids, surfactants and water 3, 4, 5. Tranfersomes and the fundamental concept of transfersomes was launched by Gregor Cevc in the year In a broad sense, transferosome is a stress responsive, elastic and an extremely adaptable aggregate.

A self-optimizing and a self-regulatory property is incorporated in the vesicle due to the composition of the bilayer and the Interdependency of the local composition.

This property helps the vesicle is traversing the different transport barriers effectively and helps the carrier in targeted and sustained delivery of active constituents in a non-invasive manner. The name implies a "carrying body" in accordance with its parent Latin and Greek name "transferred" and "soma" respectively.

Transferred literally means to carry across while "soma" means a body. An artificial vesicle is designed in such a way such that it acts like a cell involved in exocytosis which makes it appropriate for controlled and targeted drug delivery. The carrier aggregate is composed of at least one amphipathic molecule like phospholipids which when added to aqueous systems self-assemble into a bilayer of lipid which eventually closes into a lipid vesicle.

A bilayer softening agent is generally added a biocompatible surfactant to improve the bilayer flexibility and permeability. This vesicle can then adapt its shape easily and quickly, by adjusting the concentration at the local level of every bilayer component to the anxiety or stress experienced. Transfersomes differ from liposomes in that they are much softer than liposomes and are deformable to a higher extent. Therefore, are much adjustable an artificial membrane than liposomes.

Another advantage of this bilayer deformation is that it enhances the ability of the transferosome to absorb and retain water. This highly deformable and hydrophillic vesicle will steer clear of dehydration leading to a transport process much similar yet not completely identical to forward osmosis.

For example, when a transferosomal preparation is applied to a non-occluded surface which is biological, it penetrates the skin barrier and moves into the aqueous layers and gets hydrated. The barrier penetration calls for reversible deformation of the bilayer but makes sure that there is no compromise on the integrity of the vesicle nor are the barrier properties affected.

Protransfersomes High deforming ability which ensures deeper penetration in skin layers Very few. This is possible due to the ability of the vesicle to deform to a great extent which provides the mechanical stress needed to enter the skin. The main point to be kept in mind to have optimum flexibility of transfersomes is to have a suitable mix of surface active agents in proper ratios with phospholipids 6.

This flexibility minimises the possibility of complete rupture of the vesicle in the skin and helps the vesicles to follow a natural aqueous gradient across the outer layer of non-occluded skin. There are two routes through which the transfersomes can penetrate the stratum corneum through the intracellular lipid and differ in the properties of the bilayer 5.

It has been proven through confocal microscopic studies that liposomes in the intact form cannot pass through the granular epidermis and remain as such on the upper layer of the stratum corneum. Changes in the composition of the vesicle and surface properties will make sure the appropriate rate of drug release and drug deposition 4. Thus, transfersomes are ideal candidates for vesicular delivery of drugs and bioactives through the transdermal and topical delivery route. Propensity of Penetration: Since transfersomes are too large to diffuse through the skin, they need to find their own route through the organ.

Hence flow of the lipid across the skin which is chemically driven, decreases drastically when the lipid in solution form is replaced by the same amount of suspension of lipid 7. The main components of transfersome are phospholipids like soya phosphatidyl choline Vesicle forming agent , surfactants like sodium cholate or spans and tweens and solvents like ethanol, methanol etc. Method of Preparation: There are broadly two reported procedures for the transfersomes preparation.

The desired entrapment efficiency of drug is selected for optimization of the above parameters. All the other variables are kept constant while preparing a particular system 19, The edge activator that is used and the surface charge play a role in the development of these ultra-deformable vesicles for enhanced drug delivery. Characterisation of Transfersomes: The charac-terisation of transfersomes resembles that of other vesicles like liposomes, niosomes and micelles Vesicle Size, Size Distribution and Vesicle Diameter: Transmission electron microscopic studies are used to study the vesicular shape.

The size of the vesicle and size distribution is generally determined using light scattering technique. The diameter of the vesicle is determined by photon correlation spectroscopy or dynamic light scattering DLS method. The samples are prepared using distilled water, and diluted with filtered saline after passing through a membrane filter of 0. Also, they can be visualized by phase contrast microscopy without sonication using optical microscopy method.

Dynamic light scattering technique can also be used. Number of Vesicle per cubic mm: This character is very important for not only for optimizing the composition of the system but also other process variables. The formulation is diluted five times with 0. This solution is then studied by using haemocytometer with optical microscope. The transfersomes in at least 80 small squares can be counted by application of the formula:.

Total no. Entrapment Efficiency: It is expressed as the amount of the drug entrapped in percent of that what is added. It is determined by separating the unentrapped drug by mini column centrifugation followed by disruption of the vesicles using 0.

The entrapment efficiency is expressed as:. The choice of the other parameters depends on the pharmacopoeial analytical method Confocal Scanning Laser Microscopy Study: Conventional methods of light microscopy and electron microscopy have problems when it comes to fixing, sectioning and staining the sample.

There is an incompatibility generally observed between the sample and the processing techniques. This technique involves the use of lipophillic fluorescence markers and the light emitted by these markers is then used for:. Turbidity Measurement: Turbidity of the drug is measured in the solution from using a nephelo-meter 2.

Surface Charge and Charge Density: A zeta sizer is used to determine the surface charge and charge density. Penetration Ability: This is generally evaluated using fluorescence microscopy Occulsion Effect: It is considered to be helpful for permeation of topical preparations. Hydrotaxis appears to be the major driving force responsible for the permeation of transfersomes.

Occlusion effect is important to study as it prevents evaporation of water from skin thus affecting hydration forces. In-vitro Drug Release: Determined by calculating the permeation rate. The free drug from the samples which are drawn at regular intervals is obtained by mini column centrifugation. In-vitro Skin Permeation Studies: Modified franz diffusion cell having a volume of 50 mL and receiver compartment which has an effective area of 2.

Goat skin in phosphate buffer pH 7. Hair is removed from the skin and the skin is allowed to hydrate in normal saline. The skin has to be cleaned of the adipose tissues using a cotton swab. The skin can be stored in IPA at low temperatures.

While mounting, the skin should be placed with the stratum corneum facing towards the donor compartment. The stirring is carried out at a rate of rpm. Formulation equivalent to 10 mg of drug is used. At regular intervals 1 mL of aliquot is drawn and is replaced immediately with fresh phosphate buffer pH 7.

Analysis of samples is done using instrumental techniques after including the correction factors Skin Deposition Studies of Optimized Formu-lation : After the end of permeation study at the end of 24 h , the goat skin surface is washed five times with a solution containing ethanol: PBS pH 7. The skin is subjected to homo-genisation after it is cut into small pieces with the same ethanol and pH 7. After shaking it for 5min and centrifuging it for 5 min at rpm, the drug content is analysed using appropriate dilutions with phosphate buffer solution pH 7.

The result is compared, using a student's t test, with that of the control 2. In-vivo Fate of Transfersomes and Kinetics of Transfersomes Penetration: Upon transdermal delivery, transfersomes pass through the outer most layer of the skin and enter the blood circulation via the lymph and is eventually distributed throughout the body when applied under suitable conditions. Hence, transdermal transfersomes are capable of supplying to all the body tissues which are otherwise accessible to transfersomes that are sub cutaneously injected.

The velocity of the carrier penetration and speed of distribution of drug after the passage are two important factors that determine the kinetics of action of an epi-cutaneously applied agent.

The main factors of this process are:. The volume of the suspension medium that must evaporate from the skin surface determines the onset of penetration driving force. Direct biological assays are considered as the best method to study the kinetics of transfersomes penetration as the drugs enclosed in a vesicle exert their action directly under the skin surface. Local anaesthetics generally used to determine the kinetics of penetration of transfersome. Vesicles loaded with lidocaine were left on intact skin and allowed to dry.

A subcutaneous injection of lidocaine was used a control. The sensitivity of the animal to pain at the treated site after every application is assessed as a function of time. Standard liposome carrying drug applied dermally showed no analgesic effect.



Transfersomes Idea AG are a form of elastic or deformable vesicle, which were first introduced in the early s. Elasticity is generated by incorporation of an edge activator in the lipid bilayer structure. The original composition of these vesicles was soya phosphatidyl choline incorporating sodium cholate and a small concentration of ethanol. Transfersomes are applied in a non-occluded method to the skin and have been shown to permeate through the stratum corneum lipid lamellar regions as a result of the hydration or osmotic force in the skin. They have been used as drug carriers for a range of small molecules, peptides, proteins and vaccines, both in vitro and in vivo. It has been claimed by Idea AG that intact Transfersomes penetrate through the stratum corneum and the underlying viable skin into the blood circulation. However, this has not been substantiated by other research groups who have extensively probed the mechanism of penetration and interaction of elastic vesicles in the skin.


Article Information

This article was designed to review all aspects of a novel class of vesicles, transfersomes. Tranfersomes and the fundamental concept of transfersomes were launched by Gregor Cevc in the year It exists as an ultra-deformable complex having a hydrated core surrounded by a complex layer of lipid. The carrier aggregate is composed of at least one amphipathic molecule like phospholipids which when added to aqueous systems self-assemble into a bilayer of lipid which eventually closes into a lipid vesicle and one bilayer softening agent which is generally a surfactant which is responsible for the flexibility of the vesicle.


Transfersomes for Transdermal Drug Delivery




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