Hydrogels are polymeric materials which are capable of absorbing big quantities of water. They change their shape with regards to changes in the environment, such as changes in pH, temperature, the concentration of salt, etc. Because of their characteristics, they are very widespread in everyday life in the field of medicine, agriculture, pharmacy, etc.
Pressure-sensitive adhesives (PSA) are stuck by finger pressure. They have the capability to stick to the surface of the material and sufficient cohesion to enable to be removed easily from the surface of the material without any residues of glue.
Hydrogels with the characteristics of pressure-sensitive adhesives absorb an important quantity of different active substances without losing their adhesive character or elastic module. Most commonly, we encounter hydrogels with the characteristics of pressure-sensitive adhesives in transdermal systems (transdermal patches). We use transdermal patches on the surface of the skin. Thus, we avoid the metabolism of transition to the liver and the digestive system. The patches are easy-to-use and enable longer duration of therapeutic action from one application and reversible action.
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