This document summarizes hydrogel drug delivery systems. Hydrogels are hydrophilic polymer networks similar to natural tissue that can encapsulate drugs for targeted release. Drugs are released from the hydrogel matrix upon contact with specific organ or tumor molecules. Hydrogels offer adaptable targeting, more precise drug placement, and fewer side effects. Drug loading methods include microparticle encapsulation and in situ polymerization. Drug release is affected by gel degradation and swelling. Hydrogels show potential for delivering drugs to bone and cartilage and may repair cartilage more effectively than current methods. Polyvinyl alcohol hydrogels are investigated as an artificial cartilage material.
3. Hydrogel : Swellable Polymeric Materials
Hydrogels are three dimensional networks of
hydrophilic polymers.
Extremely absorbent and possess a degree of flexibility
very similar to natural tissue .
Drug encapsulated in a hydrogel matrix is only released
after contact with organ-or tumor-specific molecules
(e.g. surface proteins).
4. Advantages Of Hydrogels
Adaptable targeting system, allowing great
flexibility for many different drugs.
Offers more accurate drug placement.
Creating a more precise response and fewer
side effects.
Non-toxic and biocompatible, raising the level
of bio-safety for the patient.
Absence of Phagocytosis by macrophages.
5. Loading and Release Mechanisms in Hydrogels
In Multiphase Loading method
Drugs are modified with a microparticles that are
drugs are pre-loaded into
subsequently entrapped in hydrogels. into
crosslinkable and
Drugs are loaded
hydrogels via in situ
cleavable linker that can be
entrapment or post-
liberated once the tethers
fabrication equilibrium
are degraded hydrolytically
partitioning.
or
enzymatically.
Therapeutics-loaded micro particle
7. Delivery of bioactive molecules in Bone and
Cartilage tissue
Articular
cartilage
Cartilage is aCartilage : Absorbing impact forces,
Functions of dense and fibrous connective tissue
composed of an extracellular matrix bone, and Allowing
Transferring load to the underlying (ECM) that contains
collagen type II,movement of the joint.
low-friction proteoglycans, and water.
8. Material Development
UHMWPE
PVA - H
(Ultra-high molecular weight polyethylene )
(Poly vinyl alcohol - Hydrogel)
Carriers should have particular structure to facilitate
cellular infiltration and growth of defected
bone & cartilage tissue.
Many macrophage and giant cells are surrounding the
particle due tono foreign-body reactions.
Almost intense foreign-body reactions.
9. Poly(Vinyl Alcohol) - Hydrogel
Poly(vinyl alcohol) (PVA) gels have been formed through
Chemical Crosslinking with aldehydes or
photopolymerization. It can create harsh environments
that are potentially toxic to cells.
10. Freeze -Thawing method
Agitating under Keeping at
PVA + DMSO
a nitrogen air 20 属C
Solution
current for 10 hrs
Adding Vaccum Drying PVA
Ethanol (100 120 属C) Drygel
It gives a PVA-H with high mechanical strength, high
water content, and excellent transparency.
17. Method of Drug Delivery
Magnified view:
Matrix-based MSC After 10 days of
culture
Isolated defected Macroscopic
Cartilage Appearance:
After treatment
Bioactive factors formed by MSCs have been shown to
MSCs embedded in a collagen type I hydrogel can be
inhibit tissue scarring, suppress apoptosis, stimulate
used for tissue engineering(MSCs) can
Mesenchymal stem cells of cartilage
angiogenesis, and the damaged cartilages.
repair enhance mitosis of tissue-intrinsic
stem or progenitor cells.
18. Future Developments
References
Using injectable hollow, biodegradable nanofiber
spheres as cell carriers is likely to Suong Hyu.
1. Masanori Kobayashi and Hyon repair knee cartilage
more effectively Evaluation of Polyvinyl Alcohol-
Development and than current methods.
Hydrogels as an Artificial Atrticular Cartilage
Materials 2010, 3, 2753-2771
2. Ulrich N旦th, Andre F Steinert and Rocky S Tuan .
PVA is non-adhesive to cells and proteins, but for be
Technology Insight: adult mesenchymal stem cells can
covalently modified with cell attachment
osteoarthritis therapy
Nature Clinical Practice Rheumatology (2008) 4, 371-380
3. peptidesSayedbioactive regulation.
Maha Nasr for Aly
Intra-Articular Drug Delivery: A Fast Growing Approach
Recent Patents on Drug Delivery & Formulation 2008, 2, 231-237
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