Hydrogels Flashcards
Describe some ways to classify hydrogels
Backbone, features, crosslinking, preparation, charge distribution, homo/ copolymer…
Hydrogels are obviously composed of water. How are the polymer chains not dissolved?
Chain crosslinking, covelant bonding, counteract the solvation by water.
What are the different pore sizes in a hydrogel, and why are they important?
Macro pores, mesopores, and micropores. All relate to diffusion and solute transport on multiple levels.
From what few things are hydrogels derived from?
Sea shells, gelatins, collagens, hybrids…
Physical properties of a hydrogel are directly related to the amount of…
Crosslinking.
At equilibrium in swelling behavior, what 2 quantities are equivalent?
Thermodynamic swelling force, and chain retractive force.
How can hydrogels be used with drugs?
The solvation process allows hydrogels to be filled with drugs which are entrapped, then are released when hydrogel swells.
What does “Mc” stand for?
The average molecular weight/size between two consecutive junctions regardless of the nature of the junction. Effectively gives the crosslinking density.
What is a good way to increase the number of cross links in a hydrogel?
You can irradiate the hydrogel to create more crosslinking by addition polymerization.
Polyethylene Glycol ( PEG) was initially famous for…
Being a stealth molecule.
We used to be interested with molecules that were stealthy, but nw we are more interested in molecules that are more …
Bio functional.
What are some advantages to hydrogels?
High water content, flexible, biodegradable.
What are some disadvantages to hydrogels?
Drug loading issues–hydrophilicity, drug release diffusion rate is not consistent.
One complication in drug release, is that the rate of diffusion must match your
Therapeutic window
Matrix drug release mechanism
Drugs closer to surface release more quickly than those in the center that have further to travel.
Reservoir drug release mechanism
Drug matix surrounded by rate controlling materials.
Materials need to be thought of as more than just a mass, but
They can be used as a functional dynamic element such as a valve based on the hydrogel’s swelling.
What are some applications of hydrogels?
drug delivery, stents, contact lenses, wound healing
