Biodegradable Polymers

Question 1

Why would a medical practitioner like a material to degrade in the body?

Answer 1

• do not require a second surgery for removal
• avoid stress shielding (metal disadvantage)
• tremendous potential as the basis for controlled drug delivery

Question 2

Degradation

Answer 2

bond cleavage event leading to a change in the structure of a material, characterized by a loss of properties and/or fragmentation.

Question 3

Bond cleavage can occur through

Answer 3

hydrolysis, enzymatic activity, or exposure to light

Question 4

Resorable

Answer 4

process of eliminating the degradation products

Question 5

Erosion

Answer 5

process that results in the mas s loss of a material that may result in a change of size, shape, or mass

Question 6

Biodegradation

Answer 6

cleavage of bonds as a consequence of a biological agent, such as an enzyme, cell, or microorganism

Question 7

Surface erosion

Answer 7

erosion that is restricted to the surface of a material and proceeds via an erosion front, degradation is almost linear to time, gradually degrades

Question 8

Bulk erosion

Answer 8

erosion that occurs throughout a sample causing the whole material to degrade, entire mass loss, abrupt change in the structure

Question 9

Surface erosion applications

Answer 9

Drug delivery
- drug release rate is independent of diffusion
- easily altered by changing the device geometry

Question 10

Why do we prefer synthetic polymers?

Answer 10

• tailor-able properties
  
  • can design different monomers
• predictable lot-to-lot uniformity
  
  • consistent properties between batches as opposed to natural polymers
• free from concerns of immunogenicity
  
  • select the monomers and choose ones that aren’t immunogenic
• reliable source of raw materials

Question 11

Poly(lactic-co-glycolic) acid (PLGA)

Answer 11

Degradable polymer
- two monomers to create, glycolide and lactide
- polymer with high physiological context
- biocompatibility
- flexibility to modulate the ratio and therefore the degradation rate
- change ratio of lactic and glycolic acid can modulate degradation and mechanical strength
- different modifications to have better interactions with biological environment