Colloidal carriers

8/7/2019 Colloidal carriers

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Delivery and targeting of TherapeuticProteins using Colloidal CarrierParticles


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Colloidal Carrier Systems They are particles that are used as drug carriers into which

drugs or antigens may be incorporated in the form ofsolutions or dispersions or onto which these materials maybe adsorbed or chemically bound.

These particles have been shown to enhance the delivery ofcertain drugs across a number of natural and artificialmembranes.

They are basically Nanoparticles ranging in size from 10nm to 1000 nm (1 m). They consist of macromolecularmaterials in which the active principle (drug or biologicallyactive material) is dissolved, entrapped, or encapsulated,and/or to which the active material is adsorbed or attached.


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Liposomes


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Liposomes Their exterior lipid bilayer is very chemically reactive, thereby providing a

means to conveniently couple tags on a covalent basis.

Such tags can be antibodies, antigens, cell receptors, nucleic acidprobes, etc.

This provides significant versatility in assay formats (i.e., immunoassay,receptor-based, nucleic acid probe, etc.) possible.

With diameters ranging in size from approximately 50 nm to 800 nm, theiraqueous core encapsulates up to millions of molecules of signalgenerating markers that can be detected in a variety of different way.

A variety of different encapsulants are possible including visuallydetectable dyes (since the lipid bilayer is transparent), optically andfluorometrically detectable dyes, enzymes, and electroactive compounds.

This provides significant versatility in the detection schemes possible.


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Micelles


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Micelles

Micelle is an aggregate of amphipathic molecules in water, with thenonpolar portions in the interior and the polar portions at the exteriorsurface, exposed to water.

Amphiphilic molecules form micelle above a particular concentrationwhich is called as critical micellar concentration (CMC).

Micelles are known to have an anisotropic water distribution within theirstructure, means water concentration decreases from the surfacetowards the core of the micelle, with a completely hydrophobic (water-excluded) core.

Hydrophobic drugs can be encapsulated/solublized, into inner core.

The spatial position of a solubilized drug in a micelle will depend on itspolarity, nonpolar molecules will be solubilized in the micellar core, andsubstances with intermediate polarity will be distributed along thesurfactant molecules in certain intermediate positions.


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Dendrimers


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Dendrimers

These branched macromolecules are constructed around asimple core unit.

Dendrimers have a high degree of molecular uniformity,narrow molecular weight distribution, specific size and shapecharacteristics, and a highly-functionalizedterminal surface.

The manufacturing process is a series of repetitive steps

starting with a central initiator core. Each subsequent growthstep represents a new "generation" of polymer with a largermolecular diameter, twice the number of reactive surfacesites, and approximately double the molecular weight of thepreceding generation.


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Carbon 60 (C60)


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Carbon 60 (C60)

C60 are spherical molecules about 1nm in diameter,comprising 60 carbon atomsarranged as 20 hexagons and 12 pentagons: the

configuration of a football. Hence they find application as NanoPharmaceuticals with

large drug payload in their cage like structure.

On the other hand with development of various chemicalsubstitutes for C60, it is possible to develop functionalized C60with better drug targeting properties


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Carbon Nanotube


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Carbon Nanotube

Carbon nanotubes are adept at entering the nuclei of cellsand may one day be used to deliver drugs and vaccines.

The modified nanotubes have so far only been used to ferry a

small peptide into the nuclei of fibroblast cells.

But the researchers are hopeful that the technique may oneday form the basis for new anti-cancer treatments, genetherapies and vaccines.


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Polymeric Nanoparticles


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Quantum Dots


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Quantum Dots Consists of a semiconductor core (CdSe), coated by a shell

(e.g., ZnS) to improve optical properties, and a cap enablingimproved solubility in aqueous buffers.

Properties originate from their physical size, which rangesfrom 10100 in radius.

Due to their bright fluorescence, narrow emission, broad UVexcitation and high photostability, they have been adopted forin vitro bioimaging for real time monitoring or tracking ofintracellular process for longer time.

Large impact on some important development in differentmedical areas like diagnostic tools, MRI, in vitro and in vivodetection and analysis of biomolecules, immunoassays,DNA hybridization, non-viral vectors for gene therapy,transport vehicles for DNA, protein, drugs or cells,

fluorescence imaging of tissue, and as therapeutic tools forcancer treatment.


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Advantages increased surface area

enhanced solubility

increased rate of dissolution

increased oral bioavailability

more rapid onset of therapeutic action

less amount of dose required decreased fed/fasted variability

decreased patient-to-patient variability


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CHALLENGES

Prevention of drug from biological degradation

Effective Targeting

Patient Compliance

Cost effectiveness

Product life extension


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Methods of Drug Delivery


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Applications of variousnanosystems in cancer therapy


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Thank You!

Colloidal carriers

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