superporus hydrogel

1. Presented By:
SANTOSH THORAT
(PE/2012/315)
Dept. Of Pharmaceutics
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2. CONTENTS
 Introduction
 Formulation
 Synthetic steps
 Generations of SPHs
 SPH characterization
 Applications
 Conclusions
 References
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3. HYDROGELS:
Three-dimensional networks of hydrophilic polymer
chains that do not dissolve but can swell in water.
both solid like and liquid like properties
high biocompatibility
environmental stimuli respondent
(temperature, pH, light, specific molecules)
Ideal for controlled drug delivery
Classification: Based upon Porosity
I. Nonporous
II. Microporous
III. Macroporous
IV. Superporous
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4. Superporous hydrogels (SPHs)
 The fast swelling property is based on water
absorption through open porous structure by
capillary force.
 SWELLING PROPERTIES :
 The SPHs swell immediately upon contact with
water regardless of their size in the dried state.
 The SPHs unique property of size independent fast
swelling kinetics of SPHs is accounted for by their
interconnected open cellular structure
 The open porous structure allows extremely fast
absorption of water into the center of the dried
matrix by capillary force
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5. Formulations for SPH
Material Role
Acrylamide, Acrylic acid Monomer
Bisacylamide Cross-linker
Deionized water Solvent
Ammonium persulfate Oxidant
Tetramethyl ethylenediamine Reductant
Glacial acetic acid Foaming aid
Sodium bicarbonate Foaming agent
PEO–PPO–PEO block copolymers Foam stabilizer
H. Omidian et al. / Journal of Controlled Release 102 (2005) 3–12
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6. Synthetic steps:
 Step 1: The monomer is first diluted with certain
amount of water to reach a desired monomer
concentration.
 Step 2: Dilution with water also makes it easy to
handle the monomers. For instance, the water-diluted
glacial acrylic acid possesses superior handling
properties as compared with acrylic acid because of
its lower freezing temperature.
 Step 3 Addition of a cross-linker.
 Step 4: To produce a foam during polymerization ,
foaming aid such as glacial acetic acid and acrylic acid
are added to the monomer solution.
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7.  Steps 5: To promote polymerization, redox
couples of ammonium persulfate / sodium
metabisulfite or potassium persulfate /sodium
metabisulfite and thermal initiators, such as
ammonium persulfate or potassium persulfate ,
are used.
 Steps 6 : Since the foam stability is essential
for producing homogeneous SPHs, surfactants,
such as PEO–PPO–PEO triblock copolymers,
are used during the synthesis.
 Step 7 : Lastly, to generate gas bubbles, acid-
dependent foaming agent, such as sodium
bicarbonate is added to the formulation.
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8. Postsynthesis steps of SPHs.
 Dehydration using ethanol: helps to
stabilize the foamed product and prevent
it from shrinking.
 Drying
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9. Generations of SPHs
 The first-generation SPHs: Conventional SPHs
 Characterized by fast swelling,
 High swelling ratio,
 Weak mechanical properties.
 The second-generation SPHs: SPH composites
 Characterized by fast swelling,
 Medium swelling ratio
 Improved mechanical properties.
 The third-generation SPHs: SPH hybrids
 possess elastic properties that can be highly useful in the
development of gastrointestinal devices
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10. Structural, swelling and mechanical
properties of various SPH generations

H. Omidian et al. / Journal of Controlled Release 102 (2005) 3–12
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12. The first-generation SPHs:
Conventional SPHs
 In 1999, Chen et al prepared SPHs with fast
swelling kinetics and superabsorbent
properties for the first time.
 The dried SPHs swell fast to a large size, larger
than a few hundred times.
 Difficult to handle without breaking.
 The CSPHs are fragile against bending or
tensile stresses.
 The lack of desirable mechanical properties of
the conventional SPHs triggered the
development of the second-generation SPH
composites.
Hossein Omidian et al,JPP 2007, 59: 317–327
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13. The second-generation SPHs:
SPH composites
 A matrix-swelling additive or a composite
agent is utilized.
 As the cross-linking polymerization proceeds
throughout the solution, individual swollen
composite agent particles are connected
together through polymer chains connecting
them.
 The presence of composite agent in SPH
composites results in improved mechanical
properties over conventional
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14. The third-generation SPHs:
SPH hybrids
 a water-soluble counterpart (hybrid agent e.g.
Sodium alginate, sodium carboxymethyl cellulose
and chitosan) is employed with the third
generation SPH formulations.
 Integrated semi-interpenetrating network will
be formed first.
 Ethylenebisacrylamide has been utilized as a
thermally resistant chemical crosslinker.
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15. SPH characterization
 Surface Morphology:
SEM
 Porosity:
Mercury porositometer.
 Thermal properties:
13C nuclear magnetic resonance (NMR) and
differential scanning calorimetry (DSC).
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16.  Swelling:
 swelling and mechanical properties are generally sensitive
to the type and nature of the swelling medium (Ionic
strength,pH, salts, organic solvents and pressure).
 Where, Ms and Md are the weight of the hydrogel in the
swollen and dried states
 Measured gravimetrically and volumetrically
 swelling parameters can be evaluated at low (room
temperature) or medium/ high temperatures (body fluid
temperature of 37°C)
 Tcore -The Tcore identifies the opaque/transparent
transition in SPHs.
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17.  Mechanical properties:
 Regular mechanical testers and texture
analysers are commonly used to evaluate
SPH mechanical properties.
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18.  Gastric simulator:
 The simulator measures the amount of
energy absorbed by the sample until it fails
under certain stresses
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19.  Safety/toxicity:
 Clinical observations, clinical pathology,
chemistry and haematology, ethylene glycol
and glycolic acid were monitored during this
study.
 Induction of emesis within approximately
45min to 2 h post-dose did not cause any
safety concerns such as oesophageal
obstruction
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20. PHARMACEUTICAL
APPLICATIONS
1. Development of gastric retention devices
2. Development of fast-dissolving tablets
3. Development of diet aid
4. SPH-based gastroretentive platforms
5. Chemoembolization and occlusion devices
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21.  DEVELOPMENT OF GASTRIC
RETENTION DEVICES
 The idea was to make an oral formulation to
swell fast to a size large enough to prevent
them from passing through the pylorus.
 Maximum swelling should in about 20 minutes
because water is known to remain in the
stomach for about 30 minutes
 e.g. Superporous Hydrogels for Metoprolol
Tartrate as a Gastro Retentive System
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22.  DEVELOPMENT OF PERORAL
PEPTIDE DELIVERY SYSTEMS
 Superporous hydrogels and their composites
that increase their volume by about 200-fold.
 Such volume increase allowed the gels to
mechanically stick to the intestinal gut wall
and deliver the incorporated drug directly to
the gut wall.
 e.g. buserelin, octreotide and insulin
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23.  DEVELOPMENT OF FAST DISSOLVING -
TABLETS
 By the direct compression method is to add fine
particles of superporous hydrogels to the drug and
other excipients.
 Superporous hydrogel microparticles possess open
pore structures
 This unique porous structure allows for transport of
water through capillary forces.
 Yang et al (2004) used poly (acrylic acid)-based SPH
microparticles to make fast-melting tablets of
ketoprofen. The tablets could swell to about 80 and
50 times in distilled water and 0.2 M phosphate
buffer, respectively.
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24.  DEVELOPMENT OF DIET AID
 Superporous hydrogel tablets so that the
swollen superporous hydrogels can occupy a
significant portion of the stomach space,
leaving less space for food.
 The presence of a bulky gel or gels in the
stomach is expected to suppress the
appetite.
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25.  SPH-BASED GASTRORETENTIVE
PLATFORMS
 Requirements for a swellable gastroretentive
platform were found to be swelling rate (within
minutes), swelling capacity (preferably 8– 15% v/v),
shape, mechanical strength (resist pressures in the
range 0.5–2.0 N cm−2, preferably in the fed state),
flexibility, a controlled disintegration, ease of drug
loading, stability and pharmaceutical acceptability.
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26.  CHEMOEMBOLIZATION:
 Embolization has been used for cancer
treatment by restricting the oxygen supply
to the growing tumours.
 A chemotherapeutic agent and an anti-
angiogenic agent could be loaded into SPHs
for chemoembolization therapy.
 They fit better in the blood vessels and
provide better blocking.
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27. Non-pharmaceutical Applications
 Superporous hydrogels are also useful in the
development of simple tools for prevention
of water leakage.
 They can also be used for preventing water
spill around water-sensitive materials.
 Superporous hydrogels are useful for
making toys that can change their sizes and
colors extremely fast.
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28. Conclusions
 Superporous hydrogels are a new class of
hydrogel materials that, regardless of their
original size, rapidly swell to a large size.
 Different generations of SPHs evolved to
address the needs for certain pharmaceutical
applications.
 Various pharmaceutical and biomedical
applications of superporous hydrogels have
been made, and several products are under
development.
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29. References
 Hossein Omidian, Jose G. Rocca, Kinam Park,” ReviewAdvances
in superporous hydrogels” Journal of Controlled Release 102
(2005) 3 –12.
 Assadang Polnok , J. Coos Verhoef ,Gerrit Borchard,Narong
Sarisuta, Hans E. Junginger,” In vitro evaluation of intestinal
absorption of desmopressin using drug-delivery systems based
on superporous hydrogels” International Journal of
Pharmaceutics 269 (2004) 303–310.
 Jia Kuang, Kun Young Yuk, Kang Moo Huh,” Polysaccharide-based
superporous hydrogels with fast swelling and superabsorbent
properties”, Carbohydrate Polymers 83 (2011) 284–290.
 Cui Tang , Chunhua Yin , Yuanying Pei , Min Zhang , Lifang Wu, ”
New superporous hydrogels composites based on aqueous
Carbopol solution (SPHCcs): synthesis, characterization and in
vitro bioadhesive force studies”, European Polymer Journal 41
(2005) 557–562.
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30.  Dukjoon Kima, Kinam Park,” Swelling and
mechanical properties of superporous hydrogels of
poly(acrylamide-co-acrylic acid)/polyethylenimine
interpenetrating polymer networks”, Polymer 45
(2004) 189–196.
 Jun Chen, Kinam Park,” Synthesis and
characterization of superporous hydrogel
composites”, Journal of Controlled Release 65
(2000) 73–82.
 Hossein Omidian, Kinam Park and Jose G. Rocca,”
Recent developments in superporous hydrogels” JPP
2007, 59: 317–327.
 N Vishal Gupta , HG Shivakumar,” Development of a
Gastroretentive Drug Delivery System based on
Superporous Hydrogel”, Tropical Journal of
Pharmaceutical Research June 2010; 9 (3): 257-264.
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