Hydrogels are three-dimensionally structured networks of
hydrophilic polymers containing a large amount of water, generally more than
50% of the total weight.Hydrogels consist of polymers that swell without
dissolving in an aqueous environment (water or other biological fluid)
Properties:
ØBiodegradable and
biocompatible
ØPorous structure
ØSuitable to accommodate
high loads of water-soluble compound
ØMild preparation conditions
ØPreservation of fragile
protein 3 D structure
Natural Polymer
Based Hydrogels
Ø Chitosan-
vGlucosamine and
N-acetylglucosamine
vPositively charged at low
pH’s and uncharged and insoluble at neutral and high pH’s
ØHyaluronic Acid-
vLinear glycosaminoglycan composed of repeating
disaccharide units of D-glucuronic acid and N-acetylglucosamine
vCarboxylic groups
of hyaluronan are derivatized to obtain cross-linking
functionalities
Ø Alginates-
vUnbranched polysaccharide consisting of 1−4′-linked β-D-mannuronic acid (M)
and α-L guluronic acid
(G)
Ø Dextran- α-1,6-linked
D-glucopyranoses
Ø Collagen and Gelatin
vCollagen and gelatin hydrogels are mostly cross-linked
using gluteraldehyde or water-soluble carbodiimides-not suitable
for protein delivery
vNon-covalent
methods-entanglements of collagen fibers
Synthetic Polymer Based Hydrogels
ØPEO based
ØPoly(acrylic acid)
ØPoly(N-isopropylacrylamide)
ØPolyphosphazene
Stimuli-responsive hydrogels for protein delivery
— Smart hydrogels are
defined as materials able to undergo transitional changes in response to
environmental stimuli —Abruptly swell, shrink,
degrade, or undergo a sol−gel phase
transition when exposed to external physical or chemical triggers
Stimuli-responsive
hydrogels for protein delivery
ØPEG-g-Chitosan
ØpNIPAM-co-AA
ØPEO-PPO-PEO
ØPLGA-PEG-PLGA
ØPEG-PLGA-PEG
ØPolyphosphazenes
Hydrogel based Products
Vantas- 12-month hydrogel implant
of histrelin
ØHistrelin acetate drug core inside
a nonbiodegradable cylindrically shaped hydrogel reservoir.
Ø2-hydroxyethyl methacrylate,
2 hydroxypropyl methacrylate, trimethylolpropane trimethacrylate, benzoin methyl
ether, Perkadox-16,and Triton X-100
ReGel
-PLGA−PEG−PLGA
based thermogeling system
ØCytoryn (IL-2) and hGHD-1
ØZn−insulin
ØGlucagon-like-peptide
Tags:
Formulation