What are pH sensitive hydrogels?
A pH-sensitive hydrogel is a gel structure that is sensitive to changes in pH. These pH-sensitive hydrogels have applications in forming valves that are sensitive to a change in pH or in systems that can release a compound when the pH is changed and in pH sensors.
How are hydrogels used in drug delivery?
The swelling-controlled drug release from hydrogels uses drugs dispersed within a glassy polymer which when in contact with a bio-fluid begins swelling. The expansion during swelling occurs beyond its boundary facilitating the drug diffusion along with the polymer chain relaxation.
What are responsive hydrogels?
Stimuli-responsive hydrogels formed by various natural and synthetic polymers are capable of showing distinctive changes in their properties with external stimuli like temperature, pH, light, ionic changes, and redox potential.
What are hydrogels used for in medicine?
Hydrogels are widely used as debriding agents, moist dressings, and components of pastes for wound care. However, they do not need further wound fluids to become gels and are suitable for dry wounds .
How do pH sensitive polymers work?
pH sensitive or pH responsive polymers are materials which will respond to the changes in the pH of the surrounding medium by varying their dimensions. Materials may swell, collapse, or change depending on the pH of their environment.
What are polymers sensitive to?
Such materials can be sensitive to a number of factors, such as temperature, humidity, pH, chemical compounds, the wavelength or intensity of light or an electrical or magnetic field and can respond in various ways, like altering colour or transparency, becoming conductive or permeable to water or changing shape (shape …
What are the methods of loading drugs in hydrogels?
Hydrogels can be loaded with drugs in two different ways. In the first approach, the drug can be mixed with the precursor polymer solution and gelation occurs with the drug within the matrix, while in the second approach the hydrogel can be allowed to swell in a drug solution until equilibrium swelling is reached.
Can hydrogel crystals be used as a drug delivery system?
These crystals act as a model of a drug delivery system. The drug is first loaded onto the carrier and then it is released at a specific time and location. The tea represents the drug and the hydrogel crystal is the carrier.
Are hydrogels hydrophilic?
Hydrogel products constitute a group of polymeric materials, the hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks.
Does hydrogel dissolve in water?
A hydrogel is a crosslinked hydrophilic polymer that does not dissolve in water.
Are hydrogels safe?
When hydrogels break down, they release potassium acrylate and acrylamide. Acrylamide is a lethal neurotoxin and has been found to cause cancer in laboratory animals. Workers in the nursery and landscape industry who routinely use hydrogels may become exposed to them as they degrade and become toxic.
What are the advantages of hydrogels?
Advantages of Hydrogels The main advantage of hydrogel is that they possess a degree of flexibility very similar to natural tissue, due to their significant water content. They are biocompatible, biodegradable and can be injected. Hydrogels also possess good transport properties and easy to modify.
What are pH-responsive hydrogels?
pH-Responsive hydrogels Variations in pH are known to occur at several body sites, such as the gastrointestinal tract, vagina and blood vessels, and these can provide a suitable base for pH-responsive drug release.
What are hydrogels and how do they work?
Hydrogels are one of the upcoming classes of polymer-based controlled-release drug delivery systems. Besides exhibiting swelling-controlled drug release, hydrogels also show stimuli-responsive changes in their structural network and hence, the drug release.
What is stimuli responsive swelling of hydrogels?
Stimuli responsive swelling of hydrogels. Most of the time, drug release is observed during the swelling of the hydrogel. However, a few instances have been reported for drug release during syneresis of the hydrogel, as a result of a squeezing mechanism .
Can a hydrogel actuator be used for lipophilic drug delivery?
However, it hardly applies to lipophilic drug delivery due to their poor compatibility with hydrogels. Herein, we propose a novel method for lipophilic drug release based on a dual pH-responsive hydrogel actuator. Specifically, the drug is encapsulated and can be released by a dual pH-controlled capsule switch.