| Popis: |
Hydrogels are water-insoluble but water-swellable polymers made by a variety of chemical methods utilizing both natural and synthetic polymer backbones. They can be prepared in a wide-variety of physical forms such as foams, films, sheets, beads, powders, tubes and blocks. Thermoplastic and thermosetting forms are known and they present a very versatile class of materials capable of considerable development. The natural hydrogel material gelatin has been used in pharmaceutical formulation for more than a century and is well known in the form of soft or hard-gelatin capsules. The modern synthetic hydrogel polymers have a broad capability for specific synthetic design and the skills of polymer scientists in tailor-making the polymers and devices utilizing them will lead to a considerably expanded use of these reproducible materials in the future. This introductory presentation will be restricted to these synthetic hydrogels. |
