Biodegradable Hydrogels for Drug Delivery

From the Authors' Preface The advances made in the area of controlled drug delivery during the last two decades are remarkable ....Of the many polymeric materials, biodegradable hydrogels present unique advantages and opportunities in the development of ...delivery devices....We have undertaken the challenge of putting together information relevant to biodegradable hydrogels in one place. This book covers the mechanisms of biodegradation, types of biodegradable hydrogels, chemical and physical gels, chemical and enzymatic degradation, and examples of biodegradable drug delivery systems.

Chapters, sub-chapters and selected sub-sections, some condensed for this space. All chapters end with a section of References. Introductiono Controlled Release Drug Delivery Systems o Hydrogels: Definition, Hydrogel as a Biomaterial, Biodegradable Hydrogels Biodegradationo Definitions: Bioresorption, Bioabsorption, Bioerosion, Biodeterioration o Mechanisms: Solubilization, Charge Formation Followed by Dissolution o Chemical Hydrolysis of Polymers:Enzyme-Catalyzed Hydrolysis o Biodegradable Hydrogels Types of Biodegradable Hydrogelso Hydrogels with Degradable Polymer Backbone: Crosslinked Hydrogels, Noncrosslinked Hydrogels o Hydrogels with Degradable Crosslinking Agents: Crosslinked with Small Molecules, Crosslinked with Oligopeptides, Crosslinked with Macromolecules o Hydrogels with Degradable Pendant Chains Chemical Gelso Polymerization in the Presence of Crosslinking Agents: Introduction of Double Bonds to Macromolecules, Determination of Double Bonds on the Macromonomers o Crosslinking of Water-Soluble Polymers: Crosslinking with Functional Groups, Nonspecific Crosslinking, Determination of the Degree of Crosslinking Physical Gelso Thermoreversible Gelling System: Gels with Thermomelting Properties,Gels with Thermogelation Properties o Thermoreversible Gelling Polysaccharides: Water-Soluble Polysaccharides, Gel-Forming Polysaccharides o Physical Gelation by Ion Complexation: Polymers with Hydroxyl Groups, Carrageenan, Gellan, Pectin, Alginate, Polyphosphazenes, Other Polyanions, Chitosan o Physical Gelation by Specific Interactions: Fibrin Gel, Mucus Gel, Actin Gel, Avidin-Biotin Mediated Gel, Antibody Mediated Gel, Lectin-Mediated Gel oDetermination of the Crosslink Density Chemically-Induced Degradationo Chemically-Induced Hydrolysis in the Body: Distribution and Elimination, Factors Influencing Chemically-Induced Hydrolysis o Chemically-Induced Hydrolysis of Polyesters: Poly(glycolic Acid), Poly(lactic Acid), Polycaprolactone, Poly(ethylene Terephthalate), Poly(ß-hydroxybutyrate), Polydioxanone o Polyester Hydrogels Enzyme-Catalyzed Degradationo Properties of Enzymes o Hydrolytic Enzymes in the Body: Gastrointestinal Tract, Reticuloendothelial System, Others o Factors Influencing Enzyme-Catalyzed Reactions: Conformation of Enzymes and Substrates, Presence of Polymer Molecules o Enzyme-Catalyzed Degradation of Modified Proteins: Albumin, Gelatin, Modified Enzymes o Enzyme-Catalyzed Degradation of Modified Polysaccharides: Dextran, Starch, Amylose, Chitosan, Chondroitin-6-Sulfate Biodegradable Drug Delivery Systemso Mechanisms of Drug Release: Diffusion-Controlled Systems, Swelling-Controlled Systems, Biodegradable Systems o Drug Release From Hydrogels with Biodegradable Backbones: Hydrogels Based on Protein/Polypeptides, Hydrogels Based on Polysaccharides, Biodegradable Hydrogels Based on Polyesters o Drug Release From Hydrogels with Degradable Crosslinking Agents: Hydrogels Crosslinked with Small Molecules, Hydrogels Crosslinked with Albumin o Drug Release from Hydrogels with Biodegradable Pendant Chains Future Developmento Drug Loading o Drug Targeting o Drug Releaseo Degradation and Elimination o Use of Bioactive Polymers