SEMINAR REPORT OF DRUG DELIVERY SYSTEMS
Topic: Hydrogels as Drug Delivery Systems Reporter:
Nguyen Van Tu
Supervisor:
Dr. Le Thanh Dung Dr. Ha Cam Anh
- 51305919
HCM city, October, 2014
HOOK INTRODUCTION
Various Systems to be applied
Attract much attention
DDSs
Hydrogels: worth concerning
Each System possesses particular characteristics DDSs: Drug Delivery Systems
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SOME FIGURES
The total number of papers on hydrogels from 1950 to 2011 was 43 764. Of these, 8554 references were on the topic of drug delivery. In the drug delivery topic, the search for subtopics of proteins and genes resulted in 1674 and 284 references, respectively. - S. C. Lee, I. K. Kwon and K. Park, Adv. Drug Delivery Rev., 2013,65,17–20
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OUTLINE 1- GENERALITIES OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS 2- STRUCTURES OF HYDROGELS – TOWARDS BEING USED 3- THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
4- MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS 5- POSIBILITIES OF APPLICATION 6- INCLUSION 4
I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.1. What is gel? Coined by 19th-century Scottish
Chemist Thomas Graham is a solid, jelly-like material that
can have properties ranging from soft and weak to hard and tough. Gels are defined as a cross-linking
system, which exhibits no flow when in the steady-state. By weight, gels are mostly liquid, yet they behave like
solids due to a three-dimensional cross-linked network within the liquid. http://en.wikipedia.org/wiki/Gel
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.1. What is gel? The solid is the continuous phase and the liquid is
the discontinuous phase.
http://en.wikipedia.org/wiki/Gel
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.2. What is hydrogel? Is a Gel in which the swelling agent
is water (water is discontinuous phase). The network component of a
hydrogel is usually a polymer network. A hydrogel in which
the network component is a colloidal network may be referred to as an Aquagel.
http://en.wikipedia.org/wiki/Gel http://www.gcsescience.com/o70.htm
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.2. What is hydrogel? A hydrogel is an example of
a smart material. It can change structure in
response to salt concentration, pH and temperature.
http://en.wikipedia.org/wiki/Gel http://www.gcsescience.com/o70.htm
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.2. What is hydrogel? Hydrogels are 3D hydrophilic macromolecular networks
(matrices) that are capable of retaining a large amount of water. Having been used in a variety of applications, such as wound
dressings, transdermal patches, drug delivery devices, contact lenses, or in reconstructive surgery.
Repeating unit of LBG, Xanth, and a photograph of the obtained physical gel. - European Biophysics Journal 2007. Vol: 36(7):693-700. DOI: 10.1007/s00249-007-0158-y - Expert Rev Med Devices. 4(2), 147-164 (2007). DOI: 10.1586/17434440.4.2.147
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.3. Major definitions Cross-link
- A cross-link is a bond that links one polymer chain to another. They can be covalent bonds or ionic bonds… "Polymer chains" can refer to synthetic polymers or natural polymers . Cross-links
- http://en.wikipedia.org/wiki/Cross-link
Vulcanization with sulfur 10
I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.3. Major definitions Swelling and deswelling
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.3. Major definitions Swelling and deswelling
- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS
1.4. Hydrogels classification Classification
Contents
Classification
Contents
Origin
-
Natural Synthetic
Cross-linking method
-
Chemical (or covalent) Physical (or noncovalent)
Ionic charge (based on the nature of the pendent groups)
-
Neutral Anionic Cationic Ampholytic
Component (based on the method of preparation)
-
Homopolymer Copolymer Multipolymer Interpenetrating
-
Low swelling Medium swelling High swelling Superabsorbent
Function (based on the organization of the monomers) -
-
Nonporous Microporous Macroporous Superporous
Mechanism controlling the drug release
Water content of degree of swelling
Network Structure (porosity)
- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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Biodegradable or Nonbiodegradable Stimuli responsive Superabsorbent Diffusion Swelling Chemically controlled Environment responsive
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.1. Structures Hydrogels are cross-linked polymers that
have hydrophillic groups (-OH, -COOH, -CONH2, - SO3H, etc).
Absence of Na+ ion (remove all salts)
- http://www.gcsescience.com/o70.htm
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.1. Structures
Water molecules are attracted to the negative charges by hydrogen bonding - http://www.gcsescience.com/o70.htm
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.1. Structures
-, Journal of Microelectromechanical Systems. Vol.11, No.5, October 2002 16
II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.1. Structures - Hydrophilic domains are present, which are hydrated in a aquaous environment, creating the hydrogel structure.
- Crosslinks prevent complete mixing of the polymer chains and the aquaous phase by providing an elastic restoring force that counters the expansion of the network.
- Journal of Microelectromechanical Systems. Vol.11, No.5, October 2002 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.2. Properties to orient to applications Biocompatibility Biodegradability
Requirements
Tunable charateristics Balance between mechanical and degradation properties Adaptability to commonly used sterilization procedures (implantable systems)
- Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.2. Properties to orient to applications * Biocompatibility
- Hydrogels resemble natural living tissue more than any other class of synthetic biomaterials due to their high water content and soft consistency which is similar to natural tissue. - Hydrogels are polymeric materials that do not dissolve in water in physiological conditions. - Anti toxicity. - Advanced Drug Delivery Reviews, 11 (1993) 59-84. - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-19.9 - Journal of Materials Chemistry B, 2014, 2, 147-166.
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.2. Properties to orient to applications ** Biodegradability
- The degradation processes leading to the formation of subspecies should take place without any side effects. - The removal of the anticipated by-products from the body should be given consideration before the actual formulation of these systems. -The degradation products can be removed by excretory pathways. - Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED
2.2. Properties to orient to applications *** Tunable characteristics
- Tunable network structure to control the diffusion of drugs and tunable affinity for drugs. - Invironment responsive hydrogels for release drugs (pH, temperature, light, glucose, antigen, ionic strength, etc).
- Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels
Hydrogels Natural hydrogels
Synthetic hydrogels
Natural polymers
Synthetic polymers
Cross-linking physical bonds
Cross-linking chemical bonds
- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199 - Progress in Polymer Science. Vol 32, No.7, 2007, pp.669–697
Cross-linking polymerization of Synthetic Monomers 22
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels
ï‚— Especially,
Natural hydrogels
Synthetic hydrogels
Hydrogels with particular properties - Advanced Drug Delivery Reviews, Vol. 11, No. 1-2, 1993, pp. 59-84 - Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.1. Physical cross-linking
Hydrogels obtained are called physical gels or reversible gels
Properties
Easy to production The advantage of not using cross-linking agents
- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.1. Physical cross-linking
Heating/cooling a polymer solution Ionic interaction Complex coacervation
Means H-bonding Maturation (heat induced aggregation)
Freeze-thawing - Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.1. Physical cross-linking
CMC
H-bonding
- Transactions of the Materials Research Society of Japan, Vol 32, No 332, 713-716 26
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.1. Physical cross-linking
- H-bonded hydrogel can be obtained by lowering the pH of aqueous solution of polymers carrying carboxyl groups. - Examples of such hydrogel is a hydrogen-bound CMC (carboxymethyl cellulose) network formed by dispersing CMC into 0.1M HCl. - The mechanism involves replacing the sodium in CMC with hydrogen in the acid solution to promote hydrogen bonding. - The hydrogenbonds induce a decrease of CMC solubility in water and result in the formation of an elastic hydrogel. - Transactions of the Materials Research Society of Japan, Vol 32, No 332, 713-716 27
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking Grafting of monomers on the backbone of the polymers or
Properties
The use of a cross-linking agent to link two polymer chains
The cross-linking of natural and synthetic polymers can be achieved through the reaction of their functional groups
- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking
Using chemical cross-linkers
Methods
Grafting monomers on preformed polymer Radiation cross-linking
- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.
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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking For example: preparation of Carageenan/GA hydrogels
- Glutaraldehyde (GA) with a certain concentration (1-5 wt%) was prepared by diluting GA 25 wt% GA solution) with distilled water. The carrageenan film was immersed in GA-water mixture for 2 min.
- The surface of film was wiped with filter cloth and then cured at 1100C in oven for 25 min. The crosslinked film was soaked in water with stirring for 1 min and then in ethanol for 4 hr to remove unreacted GA. The wet hydrogels were dried at room temperature to a constant weight. - Engineering Journal, Volume 17, Issue 3, 2013, ISSN 0125-8281. DOI:10.4186/ej.2013.17.3.57 30
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking For example: preparation of Carageenan/GA hydrogels
- Engineering Journal, Volume 17, Issue 3, 2013, ISSN 0125-8281. DOI:10.4186/ej.2013.17.3.57 31
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels The samples of hydrogels were immersed in a solution of drugs.
General methods
The swollen hydrogels loaded with drug were placed in a vacuum oven and dried under vacuum at certain temperature.
The loading amount of drug in the hydrogels was specified from the decrease in the concentration of drug solution using UV spectrophotometer. The loading efficiency of hydrogels was calculated as the ratio of the final to the initial drug concentration 32
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels Powdered samples of Pc-poly(NaAA-
co-AAm), hydrogel (1 g ± 0.0001), were accurately weighted and immersed in an alkaline solution of ibuprofen (IBU, 0.54 g dissolved in 50 mL distilled water) at 0˚C for 25 h.
Ibuprofen (IBU)
Mohammad Sadeghi
The swollen hydrogels loaded with
drug were placed in a vacuum oven and dried under vacuum at 37˚C.
- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 33
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels The loading amount of drug in the
hydrogels was calculated from the decrease in the concentration of the IBU solution which was determined using a UV spectrophotometer.
Ibuprofen (IBU)
Mohammad Sadeghi
The loading efficiency of the Pectin-
based hydrogels was calculated as the ratio of the final to the initial IBU concentration.
- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 34
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels
Ibuprofen (IBU)
ï‚— Mohammad Sadeghi
- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 35
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels PEC/PAM and PEC/DEAMA hydrogels
- drug conjugate was prepared by desolving different weights of drug
Chlorotetracycline (CTC) - Antibiotic
(Chlortetracycline HCL as model drugs) (0.2, 0.3, 0.35, 0.4 and 0.5 mg) each in
distilled water to prepare (0.2, 0.3, 0.35,
Faten I. Abou El Fadl
and Nabila A. Maziad
0.4 and 0.5 mg/ml) drug concentrations. - J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 36
III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS
3.2. Preparation of drug-loaded hydrogels The dry polymer blends with known
weight 0.1 g), were soaked into the drug solutions at room temperature until the complete adsorption for 72 h. Then the amount of drug adsorbed
Chlorotetracycline (CTC) - Antibiotic
onto polymer hydrogels at different Faten I. Abou El Fadl compositions was determined by and Nabila A. Maziad using UV–Vis spectrophotometer at identical drug absorbance wavelength.
- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 37
III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.1. Mechanism
ï‚— The mechanism of drug release consists of the following phenomena:
1- Exterior diffusion, 2- Interior diffusion, 3- Desorption, 4- Chemical reactions, 5- Matrix erosion. - Roman ZARZYCKI, Zofia MODRZEJEWSKA and Katarzyna NAWROTEK. Ecological Chemistry and Engineering, Vol.17, No.2, 2010.
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.1. Mechanism
The release of water-soluble drug, entrapped in a
hydrogels, occur only after water penetrates the network to swell the polymer and dissolve the drug, followed by diffusion along the aqueous pathways to the surface of the device. The release of drug is closely related to the swelling
characteristics of the hydrogels, which in turn, is a key function of chemical architecture of the hydrogels. - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5 39
III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.2. Experiments
Placing dried and loaded sample in definite volume of different pH medium at 370C. At specific time intervals, certain aliquots of sample was withdrawn and determined by UV spectrophotometer. Released drug (%) = Rt/L x 100 - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5. - J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.2. Experiments
Baljit Singh, Ritu Bala and Nirmala Chauhan Tetracycline hydrochloride-loaded Psy-cl-poly(AAc) hydrogels were immersed in different pH buffer including distilled water, pH 2.2 and pH 7.4. After 30 min, aliquots were got and measured spectrophotometrically at λmax = 357, 358 and 362 nm. - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.2. Experiments
At higher pH, amount of released drug was higher and
quicker.
- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.2. Experiments
ï‚— Faten I. Abou El Fadl and Nabila A. Maziad
- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2.
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.3. Various environmental stimuli for triggering drug release from reponsive hydrogels
- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025
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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS
3.3. Release drug from hydrogels 3.3. Various environmental stimuli for triggering drug release from reponsive hydrogels
- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.1. Analysis of structures and characteristics There are a number of methods of analysis of
hydrogels structure which depends on the preparation, aims to define charaterization parameters. Susana Simões, Ana Figueiras, and Francisco Veiga summaried all of techniques of measurement, as table below:
- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.1. Analysis of structures and characteristics
- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.1. Analysis of structures and characteristics
- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures
Swelling study IR Spectroscopic analysis Analysis of Structure
Ultraviolet (UV) analysis Thermogravimetric analysis (TGA) 49
IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.1. Swelling studies
Target
- Calculate percentage of the total water uptake
Define some coefficients for measuring swelling kinetics
- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5. - J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.2. IR Spectroscopic analysis
Purpose
Specify functional groups at specific wavenumbers
Confirm the interaction between polymers in hydrogels
- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5. - J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.2. IR Spectroscopic analysis
The appearance of new peaks indicates the stretching of some functional groups when creating hydrogels. - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.3. Ultravillet (UV) analysis
Determining the amount of drug adsorbed onto hydrogels (effective adsorption) Goals Specifying the quantity of drug released from hydrogels in different media - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5. - J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.3. Ultravillet (UV) analysis
- N.A. Peppas et al. / Journal of Controlled Release, 62 (1999) 81–87
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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.4. Thermogravimetric analysis (TGA)
Studying thermostability of hydrogels Objectives
Measuring the compositions of hydrogels
- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 55
IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS
4.2. Focussing on analysis of structures 4.2.4. Thermogravimetric analysis (TGA)
- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 56
V. POSIBILITIES OF APPLICATION
5.1. View of applications In recent years, there has been remarkable process in the
development of clinically applied hydrogels. Since 1960, the copolymers of 2-(HEMA) and ethylene
dimethacrylate have been applied for their use in contact lens, urinary catheters, wound dressing and surgical gloves, etc. After that, development of clinically applied hydrogels
has attracted research regards.
- Journal of Materials Chemistry B, 2014, 2, 147-166. 57
V. POSIBILITIES OF APPLICATION
5.1. View of applications
- Journal of Materials Chemistry B, 2014, 2, 147-166.
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V. POSIBILITIES OF APPLICATION
5.1. View of applications
- Journal of Materials Chemistry B, 2014, 2, 147-166.
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V. POSIBILITIES OF APPLICATION
5.2. Some of specific applications Implanting degradable insulin loaded-poly(NIPAAm-
co-Dex-lactateHEMA) hydrogels to rat’s conjunctiva for treating diabetic retinopathy.
- G.P. Misra et al. / Biomaterials 30 (2009) 6541–6547
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V. POSIBILITIES OF APPLICATION
5.2. Some of specific applications Results of research demonstrated that both hydrogels and
their degradation products were non-toxic to cultured R28 retinal cells, and accordingly the hydrogels have potential for in vivo implantation. None of inflammation or morphological changes in eyes implanted insulin loaded hydrogels.
- G.P. Misra et al. / Biomaterials 30 (2009) 6541–6547
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V. POSIBILITIES OF APPLICATION
5.2. Some of specific applications Investigating starPEG-heparin-based hydrogels loaded by some Growth Factors (GFs): bFGF and EGF. Applying to treat acute kidney injury on mice.
The results confirm possitive indication to ultilizing hydrogels for GFs delivery.
- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255
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V. POSIBILITIES OF APPLICATION
5.2. Some of specific applications
- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255
63
V. POSIBILITIES OF APPLICATION
5.2. Some of specific applications No visual signs of inflammation for both the control
and the GFs treated mice. The hydrogels alone did not induce treatment
efficency. There was the difference of proliferation between the
left injected GF and the right non-injected GF kidney.
- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255
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V. POSIBILITIES OF APPLICATION
5.3. Some drawbacks of hydrogels in DDSs May release toxic subtances Low mechanical strength ->limits load bearing
Hydrogels Moist -> sterility, shipping, packing Some risks of infection, delayed wound healing. - Journal of Materials Chemistry B, 2014, 2, 147-166.
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VI. SUMMARY
Hydrogels are considered one of drug delivery
systems which has crucial position in medical applications. There has been a great number of researches related to hydrogels, which aims to apply to target diseases on the majority of human body. Besides advantages, hydrogels also have some drawbacks requiring the advance of design of
hydrogels’ properties. 66
Good day 67