This document outlines the synthesis and characterization of multifunctional smart hydrogels. It begins with an introduction to hydrogels and their properties like biocompatibility and ability to respond to environmental stimuli. Next, it discusses the motivation and objectives which are to develop a hydrogel based on poly(acrylic acid-co-N-vinylpyrrolidone) copolymer for controlled drug release. The document then covers the synthesis and characterization of the hydrogel through techniques like XRD, SEM, and studies of swelling ratio, gel percentage, and drug release kinetics. The goal is to create a hydrogel with high swelling ability that can release drugs in a controlled manner over extended time periods.

1. By
Sayan Ganguly
Synthesis and characterization of multifunctional
superabsorbent smart hydrogels
19 December 2016

2.  Introduction and Literature Survey
 Motivation and Objective
 Synthesis of polyethylene glycol/poly(acrylic acid-co-N-vinylpyrrolidone)
composite hydrogel for controlled release of drug
 Results and Discussion
 Conclusion
 Future plan
 References
 Acknowledgement
Outline

3.  Three-dimensional networks of hydrophilic polymer chains that
do not dissolve but can swell in water
 High biocompatibility
 Environmental stimuli responding
(temperature, pH, light, specific molecules)
 Mechanically strong
 Capable of achieving high drug loading
 Simple to administer and remove
 Free of leachable impurities
 Easy to fabricate and sterilize
Introduction
Hydrogels

4. 1894
• First coined the term hydrogel by van Bemmelen
1958
• PVA hydrogels via gamma irradiation by Danno
1960
• P(HEMA) gel for biological use by Wichterle & Lim
1968
• Poly(NIPAM) solution displaying temp. dependent phase transition By Heskins & coworkers
1990
• PNIPAM hydrogel via redox initiated polymerization by Otake & Inomata
1995
• Natural-synthetic hybrid hydrogels by Cascone et al.
1997
• Temperature responsive PEG-PLA hydrogels by Jeong et al.
2001
• PEG hydrogels via Michael addition by Elbert et al.
2006
• PEG hydrogels via click chemistry by Ossipov et al.
Literature Reviews

5. 2010
•Age of smart hydrogels begins with hybrid fillers
2010
•Graphene oxide/PVA hydrogels for controlled release by Bai et al.
2012
•Drug delivery from PHPMC matrix by Peppas et al.
2014
•pH-responsive poly(itaconic acid-co-vinylpyrrolidone) hydrogel by Peppas et al.
2016
•Shape memory acrylamide-DNA hydrogel by Hu et al.
Cond…
J. Mat. Chem. B, 3.18, 2015, 3654-3676.

6. 6
 Drug delivery, scaffolds, food preservation, biosensors
 Study cell and tissue physiology
 Large water content and rubbery consistency makes hydrogels great
mimics for living tissue
Scope and motivations
9 December 2016
Scope and motivations
 Aim is to develop a high swelling hydrogel based on Poly(AA-co-NVP)
copolymer hydrogel which is a vehicle for drug release in controlled
fashion.
Sequential semi-IPN based on this polymer can enhance gel strength
and better swelling in psychological pH.
 Developing hydrogel with withstanding drastic pH fluctuations.

7. Sustained release:
 Any dosage form that provides medication over an extended
time
 Timed release, prolonged release etc.
Controlled release:
 Denotes that the system is able to provide some actual
therapeutic control, whether this be of a temporal nature,
spatial nature, or both
Terminology

8. With traditional administration, the
drug active must remain between a
maximum blood level value which may
represent a toxic level and a minimum
value below which the drug is no longer
effective
With controlled administration, the
blood levels are constant between
the desired maximum and
minimum for an extended period
of time
Traditional vs. Controlled Release Drug Dosing

9. Origin Natural
Synthetic
Water content or degree of swelling Low swelling
Medium swelling
High swelling
Superabsorbent
Porosity Nonporous
Microporous
Macroporous
Superporous
Cross-linking Chemical (covalent bonding)
Physical (non-covalent bonding)
Biodegradability Biodegradable
Nondegradable
Classification of hydrogels on account of various criteria

10. Chemical hydrogels Physical hydrogels
▪ Hydrogen bonding
▪ Hydrophobic interaction
▪ Crystallinity
▪ Stereocomplex formation
▪ Ionic complexation
Covalently crosslinked Noncovalently crosslinked
Thermoset hydrogels Thermoplastic hydrogels
Volume phase transition Sol-gel phase transition
Reliable shape stability and
memory
Limited shape stability and
memory
10
Hydrogel Fabrication
9 December 2016

11. Polymerization of water soluble monomers in the presence of bi-
or multifunctional cross-linking agent
+
Monomer Crosslinker
Vinyl group-containing water-soluble polymers
Hydrogel network
or
Chemical crosslinking
Hydrogel Fabrication
119 December 2016

12. One self-made study: Reaction Scheme for hydrogel preparation
Ref: Ganguly, Sayan, and Narayan C. Das. "Synthesis of a novel pH responsive phyllosilicate loaded polymeric hydrogel based on poly (acrylic acid-co-N-
vinylpyrrolidone) and polyethylene glycol for drug delivery: modelling and kinetics study for the sustained release of an antibiotic drug." RSC
Advances 5.24 (2015): 18312-18327.

13. XRD and SEM study
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XRD of pristine PEG and hydrogel
SEM image
of porous structure
of hydrogel
SEM image of
Filler loaded
hydrogel

14. pH reversibility (switch on-off behavior) of the gels
9 December 2016 14
SwellRatio

15. Yield% =
𝐜𝐨𝐧𝐬𝐭𝐚𝐧𝐭 𝐝𝐫𝐲 𝐰𝐭.𝐨𝐟 𝐠𝐞𝐥 𝐚𝐟𝐭𝐞𝐫 𝐫𝐞𝐚𝐜𝐭𝐢𝐨𝐧
𝐰𝐭.𝐨𝐟 𝐫𝐞𝐚𝐜𝐭𝐚𝐧𝐭𝐬 𝐭𝐚𝐤𝐞𝐧 𝐢𝐧𝐢𝐭𝐢𝐚𝐥𝐥𝐲
Gel% =
𝐰𝐭.𝐨𝐟 𝐱𝐞𝐫𝐨𝐠𝐞𝐥
𝐜𝐨𝐧𝐬𝐭𝐚𝐧𝐭 𝐝𝐫𝐲 𝐰𝐭.𝐨𝐟 𝐠𝐞𝐥 𝐚𝐟𝐭𝐞𝐫 𝐫𝐞𝐚𝐜𝐭𝐢𝐨𝐧
Sol% = 100 – Gel%
Rs=
𝑾 𝒔−𝑾 𝒅
𝑾 𝒅
Rs= swelling ratio
Ws = weight of swollen hydrogels
Wd = weight of dried hydrogels
15
Effect of reaction variables on synthesis
9 December 2016

16. Effect of medium salinity and pH
Concentration(M) pH

17. Effect of reaction variables
9 December 2016 17
Geltime(min)
Geltime(min)
Swellratio
Geltime(min)
Swellratio
Swellratio

18. 1st order swelling kinetics: SRt= 𝑄 𝑒 1 − 𝑒−𝑘1 𝑡
Swelling kinetics study of hydrogels
9 December 2016 18

19. Case I
Anomalous
Case II
Mechanism behind swelling
9 December 2016 19

20. De-swelling of hydrogels
9 December 2016 20
Free water
Interstitial
water
Bound
water

21. Formation of hydrogel and drug loading
9 December 2016 21

22. x
x
H2C C
CH3
C O
O-
H2C C
CH3
-OOC
Complexation and pH responsive hydrogels
H2C C
CH3
C O
H2C C
CH3
HOOCHO

23. Drug release and Peppas model
𝑭 𝑫 =
𝒎 𝑫𝒕
𝒎 𝑫𝒆
= 𝑲 𝑲𝑷 𝒕 𝒏
mDt amount of drug released at time t
mDe are and infinity (at equilibrium)
KKP = Peppas constant
n = drug release exponent
n
0.5
1.0
0.5 – 1.0
Case I
Anomalous
transport
Case II
9 December 2016 23