Hydrogels assignment 2
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This document discusses hydrogels, which are cross-linked polymer networks that can absorb large amounts of water. It classifies hydrogels based on their structure, charge, and mechanism of drug release. It also outlines common monomers used to synthesize hydrogels and various preparation methods like crosslinking. The document notes advantages like biocompatibility and ability to inject hydrogels, as well as disadvantages such as low mechanical strength. It concludes that hydrogels can be used for targeted drug delivery, as biosensors, and in wound healing and tissue regeneration due to their responsiveness to stimuli.
Hydrogels assignment 2
- 1. Hydrogels -Biomaterial Sciences Under the guidance of: Dr. Monalisa Mukherjee By: Sukriti Singh BTBM/13/242 A0523113081 Sem 3, Sec D AIB, Amity University, Noida
- 2. CONTENTS: • Introduction • Classification of Hydrogels • Advantages of Hydrogels • Disadvantages of Hydrogels • Types of Hydrogels • Monomers Used In The Synthesis of Synthetic Hydrogels • Method of Preparation of Hydrogels • Common Uses For Hydrogels • Summary and conclusions • References
- 3. Introduction Hydrogel is a network of polymer chains that are hydrophilic, water insoluble, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are highly absorbent natural or synthetic polymers. Hydrogels are cross-linked polymer networks that absorb substantial amounts of aqueous solutions. Hydrogels can contain over 99.9% water. Hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids. The networks are composed of homopolymers or copolymers, and are insoluble due to the presence of chemical crosslinks (tie-points, junctions), or physical crosslinks, such as entanglements or crystallites. The high water content of the materials contributes to their biocompatibility. These crosslinks provide the network structure and physical integrity. These hydrogels exhibit a thermodynamic compatibility with water which allows them to swell in aqueous media.
- 4. Classification of Hydrogels STRUCTURE • Amorphous Hydrogels • Semi-crystalline Hydrogels • Hydrogen Bonded Hydrogels CHARGE • Neutral Hydrogels • Anionic Hydrogels • Cationic Hydrogels • Ampholytic Hydrogels MECHANISM OF DRUG RELEASE • Diffusion Controlled Release Systems • Swelling Controlled Release Systems • Chemically Controlled Release Systems • Environment Responsive Systems METHOD OF PREPARATION • Homopolymer Hydrogels • Co-polymer Hydrogels • Multi Polymer Hydrogels
- 5. Monomers Used In The Synthesis Of Synthetic Hydrogels:
- 7. Methods of preparation of Hydrogels Crosslinking Isostatic Ultra High Pressure Nucleophilic Substitution Reaction Using Gelling Agents Use Of Irradiation Freeze Thawing
- 8. Advantage of Hydrogels: Hydrogels possess a degree of flexibility very similar to natural tissue, due to their significant water content. Entrapment of microbial cells within Hydrogel beads has the advantage of low toxicity. Environmentally sensitive Hydrogels have the ability to sense changes of pH, temperature, or the concentration of metabolite and release their load as result of such a change. Timed release of growth factors and other nutrients to ensure proper tissue growth. Hydrogels have good transport properties. Hydrogels are Biocompatible. Hydrogels can be injected. Hydrogels are easy to modify. 8
- 9. Disadvantages of Hydrogels: Hydrogels are expensive. Hydrogels causes sensation felt by movement of the maggots. Hydrogels causes thrombosis at Anastomosis sites. The surgical risk associated with the device implantation and retrieval. Hydrogels are non-adherent; they may need to be secured by a secondary dressing. Hydrogels used as contact lenses causes lens deposition, hypoxia, dehydration and red eye reactions. Hydrogels have low mechanical strength. Difficulty in handling. Difficulty in loading. Difficulty in Sterilization. 9
- 10. Common Uses For Hydrogels: MISCELLANEOUS • Used as Medical electrodes in ECG. • Used as Breast implants. BIOTECHNOLOGY • Used as Biosensors that are responsive to specific molecules, such as glucose or antigens. SANITARY PURPOSE • Used in disposable diapers where they absorb urine, or in sanitary napkins. 10
- 11. Summary & Conclusion: Recent developments in the field of polymer science and technology has led to the development of various stimuli sensitive hydrogels like pH, temperature sensitive, which are used for the targeted delivery of proteins to colon, and chemotherapeutic agents to tumors. Some environmental variables, such as low pH and elevated temperatures, are found in the body. For this reason, either pH-sensitive and/or temperature sensitive hydrogels can be used for site-specific controlled drug delivery. Hydrogels that are responsive to specific molecules, such as glucose or antigens, can be used as biosensors as well as drug delivery systems. The hydrogels may be suitable as a wound substitutes and can be used in wound healing. New synthetic methods have been used to prepare homo- and co- polymeric hydrogels for a side range of drugs, peptides, and protein delivery applications. Hydrogels are also used in regenerating human tissue cells. 11
- 12. References: 1.Remington: The Science and Practice of Pharmacy. Published by Lippincott Williams & Wilkins, 2005.Twenty-First Editions. P.NO. 294,756,867,868. 2. Handbook of Pharmaceutical Excipients, A. Wade and P.J. Weller ed., The Pharmaceutical Press, London, 1994, pp. 229–232. 3. British Pharmacopoeia 2002, the Stationary Office, London, 2002, p. 2092–2094. 12