Which is pH sensitive polymer?

Although many sources talk about synthetic pH sensitive polymers, natural polymers can also display pH-responsive behavior. Examples include chitosan, hyaluronic acid, alginic acid (link to Wiki article: Alginic acid) and dextran. Chitosan, a frequently used example, is cationic.

Which polymer shows pH dependent swelling?

The chemical structure of xanthan is shown in Figure 8. Figure 8. Chemical structure of Xanthan. Xanthan, being an ionic polymer, containing a carboxylic group on one of the side chain of glucuronic acid is pH sensitive and shows much swelling in basic environment due to complete ionization of the carboxylic group.

What is a responsive polymer?

Stimuli-responsive polymers or so-called smart polymers are macromolecules that are sensitive to certain triggers from the external environment, including temperature, light, electrical or magnetic fields, and chemicals.

How do pH sensitive hydrogels work?

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.

What are temperature responsive polymers used for?

Temperature-responsive polymers or thermoresponsive polymers are polymers that exhibit a drastic and discontinuous change of their physical properties with temperature. The term is commonly used when the property concerned is solubility in a given solvent, but it may also be used when other properties are affected.

What are stealth nanoparticles?

Stealth nanoparticles grafted with poly(ethylene glycol) … PEGylation technology has been widely used for improving the PK of a variety of nanoparticles. PEGylated nanoparticles are often referred as stealth nanoparticles, because they escape the surveillance of RES better than the control nanoparticles.

What are the two categories of polymers?

Polymers fall into two categories:

How does pH affect the swelling of hydrogels?

Effect of pH on swelling Slight change in swelling ratio of the biomineralized hydrogels has been noticed when placed in various pH of the aqueous solution. It can also be noticed that irrespective of sample thickness at neutral pH = 7, all samples show a higher value of swelling ratio.

What is the normal pH of gastric fluid?

The normal volume of the stomach fluid is 20 to 100 mL and the pH is acidic (1.5 to 3.5). These numbers are converted to actual acid production in units of milliequivalents per hour (mEq/hr) in some cases.

What is a responsive material?

The ability of a material to respond to different stimuli is related to their physico-chemical characteristics. … Stimuli-responsive materials have numerous applications in the biomedical field, from drug delivery systems to diagnostics and treatment.

What are environment responsive polymers?

Stimuli-responsive polymers are polymers that respond with noticeable physical or chemical changes in their behaviors with a small change of environmental stimuli variations.

What are smart polymers examples?

Examples of smart polymers are those that undergo rapid, reversible phase changes in response to small changes in environmental conditions. Ista and Lopez employed poly(N-isopropylacryl-amide) (PNIPAAM), a polymer that is soluble in water below, but insoluble above, 32C.

What are thermosensitive hydrogels?

Thermosensitive hydrogels are very important biomaterials used in drug delivery systems (DDSs), which gained increasing attention of researchers. … By in vivo injection, the hydrogels formed non-flowing gel at body temperature.

Are plants and animals pH sensitive?

All plants and animals are sensitive towards pH. Living organism works within the narrow range of pH. Our body also works within the narrow range of pH of 7.0 to 7.8 only. If this pH range increases or decreases, living organism find it difficult to survive.

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.

What is Ucst and Lcst?

Partially miscible polymer solutions often exhibit two solubility boundaries, the upper critical solution temperature (UCST) and the lower critical solution temperature (LCST), which both depend on the molar mass and the pressure.

What is cloud point in polymer?

The cloud-point temperature (CTP) is the temperature at which phase separation starts. At this temperature the solution becomes turbid/cloudy due to the formation of polymer-rich emulsion droplets. Cloud-point is dependent on polymer concentration.

Do all polymers have Lcst?

In fact, every polymer with the appropriate hydrophilichydrophobic balance will show LCST behavior. However, this rather easy access to the area of thermoresponsive LCST polymers has led to rapid growth of this research area with many new research groups entering the field from a wide range of application areas.

What are stealth polymers?

Polymers Used to Coat Nanocarriers In drug delivery, the term stealth, translated from the low observable technology applied to military tactics, refers to nanovehicles that are invisible to the biological system involved in clearance of particle from the bloodstream, namely, RES and Kupffer cells.

Is Peg a nano particle?

PEG nanoparticles are highly stable considering different physiological factors such as stability of the nanoparticle, half-life of the nanoparticle, and nanoparticle extravasation. These qualities make it a well-organized, versatile nanocarrier for cancer therapy [14].

What is the half-life of liposomes?

Its reported half-life is 60117 hours, depending on the dose (Boulikasetal2005 ;Stathopoulosetal2005).

What are the 4 types of polymers?

Synthetic polymers are human-made polymers. They can be classified into four main categories: thermoplastics, thermosets, elastomers, and synthetic fibers.

What are addition and condensation polymers?

Addition polymerization is the process of repeated addition of monomers that possess double or triple bonds to form polymers. Condensation polymerization is a process that involves repeated condensation reactions between two different bi-functional or tri-functional monomers.

What are the three basic categories of polymers?

Polymer Chemistry: Classification of Polymers. The most common way of classifying polymers is to separate them into three groups – thermoplastics, thermosets, and elastomers. The thermoplastics can be divided into two types – those that are crystalline and those that are amorphous.

What does gastric pH of 4 or lower indicate?

A pH of 4 has been defined as a threshold below which refluxed gastric contents become injurious to the oesophagus.

What would happen if the pH of the stomach was 7?

When we eat crude food, its proteins work with the salivary amylase to start digestion. Complete answer: When the pH of the stomach is made 7 then protein digestion will affect as pepsin work as a pH of 2 to 3 and it does not activate because the enzyme is highly precise about their function.

What is the role of pH in stomach?

The pH of our stomach is critical to the digestion of many nutrients and acts as the first line of defense against harmful bacteria and viruses. The stomach is a reservoir of strong acid, with a much lower pH than in any other part of our digestive system.