Nano Gel
The term ‘nanogels’ defined as the nanosized particles formed by
physically or chemically crosslinked polymer networks that is swell in a good
solvent. The term “nanogel” was first introduced to define cross-linked
bifunctional networks of a polyion and a nonionic polymer for delivery of
polynucleotides (cross-linked polyethyleneimine (PEI) and poly (ethylene
glycol) (PEG) or PEG-cl-PEI). Sudden outbreak in the field of nanotechnology
have introduced the need for developing nanogel systems which proven their
potential to deliver drugs in controlled, sustained and targetable manner.
superiority than other delivery system
The particle size and surface properties can be manipulated to
avoid rapid clearance by Phagocytic cells, allowing both passive and active
drug targeting.Controlled and sustained drug release at the target site,
improving the therapeutic efficacy and reducing side effects. Drug loading is
relatively high and may be achieved without chemical reactions; this is an
important factor for preserving the drug activity. Ability to reach the
smallest capillary vessels, due to their tiny volume, and to penetrate the
tissues either through the paracellular or the transcellular pathways. Highly
biocompatible and biodegradable.
Properties
of nanogels
Biocompatibility
and degradability
Nanogel based drug delivery system
is highly biocompatible and biodegradable due to this characteristics it is
highly promising field now a days.
Swelling
property in aqueous media
The most beneficial feature of
Nanogels is their rapid swelling/de-swelling characteristics.
Higher drug loading capacity
The properties of higher drug
loading capacity of nanogels depend on the functional group present in the
polymeric unit. These functional groups have a tremendous effect on drug carrying
and drug-releasing properties, and some functional groups have the potential to
conjugate with drugs/antibodies for targeting applications.
These pendent functional groups of
polymeric chains contribute toward establishing hydrogen bonding or vander
Waals forces of interactions within the gel network and thus facilitate the
drug-carrying efficiency. Moreover, the presence of functional groups at
interface with drug/protein molecules is also responsible for higher loading.
Particle size
Nanogels typically range in size of
20–200 nm in diameter and hence are effective in avoiding the rapid renal
exclusion but are small enough to avoid the uptake by the reticuloendothelial
system.
Solubility
Nanogels are able to solubilize
hydrophobic drugs and diagnostic agents in their core or networks of gel.
Electromobility
Nanogels could be prepared without
employing energy or harsh conditions such as sonication or homogenization,
which is critical for encapsulating biomacromolecules.
Colloidal stability
Nanogels or polymeric micellar
nanogel systems have better stability over the surfactant micelles and exhibit
lower critical micelle concentrations, slower rates of dissociation, and longer
retention of loaded drugs.
Non-immunologic response
This type of drug delivery system
usually does not produce any immunological responses.
Others
Both type of drugs (hydrophillic and
hydrophobic drugs and charged solutes) can be given through nanogel. Such
properties of nanogel are significantly influenced by temperature, presence of
hydrophilic/ hydrophobic groups in the polymeric networks, the cross-linking
density of the gels, surfactant concentration, and type of cross-links present
in the polymer networks.
Advantages of Nanogel Drug Delivery
Approach:
1) It provides protection from
biodegradation of drugs inside the body.
2) Physical properties like size of
nanogels can be easily adjusted and maintained according to the desired
delivery molecule.
3) Low amount drug is required as well
as quantity of doses is reduced.
4) Improves the bioavailability of the
drug molecule and reduce the toxicity of the drugs.
5) Drugs loaded nanogels can be
delivered inside the body with no adverse or side effects as well as can be
applied topically
Disadvantages of Nanogels:
1) It requires expensive techniques to
completely remove the solvent sand surfactants at the end of the process.
2) Sometimes, traces of surfactants can
cause toxicity.
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