Hemodialysis: Chapter 1, Physiological Principles of Hemodialysis - Dr.Gawad
sheetal (1).ppt
1. Synthesis and Characterization of
Hydrogels and its application
Under the supervision of : Presented by :
Mr. Sumit Kumar Rai Sheetal Chanyal
Assistant Professor M.tech (1st Year)
G.B.Pant Engineering College
2. Hydrogels are cross-linked, water swollen, three dimensional
insoluble hydrophilic polymeric structure produced by reaction
between monomers.
They have inherent property to absorb and retain
large quantity of water up to 1000 times their dry weight.
Hydrogels
3. Why Hydrogels : In Drug Delivery…
Safe degradation products
Biocompatible
High loading with ensured molecule efficacy
High encapsulation
Variable release profile
Stable
Inexpensive
High quality
5. Difference between………………….
Advantages
Precise control and mass
produced
Can be tailored to give a wide
range of properties (can be
designed to meet specific needs)
Low immunogenecity
Minimize risk of biological
pathogens or contaminants
Disadvantages
Low biodegradability
Can include toxic substances
Advantages
Generally have high
biocompatibility
Intrinsic cellular interactions
Biodegradable
Cell controlled degradability
Low toxicity byproducts
Disadvantages
Mechanical Strength
Batch variation
Animal derived materials may pass
on viruses
Natural Synthetic
6. Properties of hydrogels
1. Swelling properties are influenced by changes in the
environment like :-
pH
Ionic strength
Pressure
2. Can be Biodegradable, Bioerodible, and Bioabsorbable.
3. Can be degraded in controlled fashion.
4. Pore Size
Temperature
Solvent composition
Electrical potential
Cont……..
7. 5. Fabrication techniques
6. Shape and surface/volume ratio
7. H2O content
8. Strength
9. Swelling activation
Properties of hydrogels
9. Membrane Preparation
Step 1 • Prepare 10 % PVA Solution.
Step 2
• Stirred for 20 min with Cross linker.
Step 3
• Add 1 M HCl as Catalyst.
Step 4
• Pour the solution in Petri plate
Step 5
• Left for drying
Step 6
• Remove membrane from plate after drying
for 24 h.
10. Step 7
• Curing is done at 80 0C.
Step 8
• Required Membrane is obtained
Step 9
• Characterization
(Contd…)
11.
12. S. No. Cross-Linker (CL) Structure
Parts by
weight
Sample
designation
PVA TA
1. Tartaric Acid 100 30 PTA30
100 25 PTA25
100 20 PTA20
100 15 PTA15
Polymer:-
Materials Used
Cross Linker:-
Polyvinyl alcohol
13. Swelling
Network starts to swell due to the thermodynamic compatibility of the polymer
chains and water.
Swelling in chemical (cross-linked) polymers is dependent on the solvent
Swelling force is counterbalanced by the refractive force induced by the cross-
links of the network
Swelling equilibrium is reached when these two forces are equal.
Degree of swelling can be quantified by:
Ratio of sample volume in the swollen state to volume in the dry state
(Contd.)
14. With increase of cross-linking, swelling decreases significantly for all
the three types of hydrogels.
Ratio of functional group of monomer and cross-linker primarily
dictate the swelling besides reactivity of cross-linker.
15. Hemocompatibility test
• Sample collection
Samples whole blood was collected from healthy
donor with citrated (3.2%) 1.8 ml vacuum blood-
collection tubes and transported on ice.
The blood sample, centrifuged at 2000 × g for10
min at 4◦C to obtain Platelet Poor Plasma (PPP),
16. Hemolytic assay protocol
BC samples were equilibrated in phosphate buffer
saline (PBS) and then transferred to a tube
containing 7 ml of PBS.
1 ml of diluted blood (hemoglobin concentration of
10 mg/ml)was added and incubated at 37◦C for 3 h
in a water bath.
The tubes were gently inverted every 30 min to
promote contact between blood and samples.
17. The membranes were then removed with sterile
tweezers and the diluted blood centrifuged at 750 ×
g for 15 min.
1 ml of Drabkin’s reagent was added to 1 ml of
supernatant and incubated for 15 min at room
temperature, and finally the absorbance was read at
= 540 nm.
Hemoglobin concentration was calculated using a
calibration curve previously prepared with human
hemoglobin and calculated using the formula:
HC = A × m × d (A, absorbance; m slope of the
hemoglobin curved, dilution) and presented as
percentage.
18. Biomedical Uses for Hydrogels
• Scaffolds in tissue engineering.
• Sustained-release delivery systems
• Provide absorption, desloughing and debriding capacities of necrotics
and fibrotic tissue.
• Hydrogels that are responsive to specific molecules, such as glucose or
antigens can be used as biosensors as well as in DDS.
• Disposable diapers where they "capture" urine, or in sanitary napkins
• Contact lenses (silicone hydrogels, polyacrylamides).
• Lubricating surface coating used with catheters, drainage tubes and
gloves
• Breast implants
19. •Dressings for healing of burn or other hard-to-heal wounds. Wound gels
are excellent for helping to create or maintain a moist environment.
• Reservoirs in topical drug delivery; particularly ionic drugs, delivered by
iontophoresis
• Artificial tendon and cartilage
• Wound healing dressings (Gelperm)
• non-antigenic, flexible wound cover
• permeable to water and metabolites
• Artificial kidney membranes.
• Artificial skin.
• Maxillofacial and sexual organ reconstruction materials
• Vocal cord replacement.
• Butt injections.
Contd…..
20. Conclusion
• The swelling behavior of the hydrogels can be adjusted
within the required range by varying the amount of cross-
linker.
• Cross-linkers with same chain length and different
structures provide almost similar type of swelling behaviour
in water.
• These PVA hydrogels provide pH dependent swelling due
to the presence of acid cross-linker.
21. Future Scope
• These pH dependent hydrogels may find application in
biomedical field.
• These hydrogels may find application in colon specific drug
delivery system.
• Biocompatibility of the hydrogels other than PMA should be
evaluated.
• More precise control over the extent of swelling should be
achieved.
