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Flashcards in 4. Drug delivery Deck (24)
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1

Give examples of applications of nanotechnology in life sciences which use the iv delivery route.

- treatment of cancer, siRNA and gene delivery, intracellular infections.

2

Give examples of applications of nanotechnology resulting in improved drug delivery via the oral route.

improvement of solubility, delivery of peptides, proteins and vaccin

3

describe the evolution of drug delivery systems since the 1970s

sof natural organic drug carriers, soft synthetic drug carriers, hard inorganic particles for imaging and drug delivery

4

Mention 5 forms in which can you deliver a drug using nanomaterials.

as a nanocrystal of the active substance or embeded in nanocarriers (depo, matrix, dendrimer, layer-by-layer)

5

What are the possible benefits of using nanomaterials in drug delivery?

-tissue targetting (efficiency, toxicity), protection against degradation (clearance, dosing frequency), use of enhanced permeability and retention effect (EPR)

6

Which pre-requisits must be fulfilled before a drug can be absorbed into the blood?

the active substance needs to have solubility and permeability

7

What are the consequences when a drug is poorly soluble?

- poor and variable bioavailability, no dose-response, slow onset of action

8

How are poorly soluble compounds being called?

brick dust, grease balls

9

The Lipinski rule of 5 is used for the selection of candidate drugs for further development. Which type of drugs?

drugs to be given orally, absorbed via passive diffusion.

10

Give the rules of Lipinski.

-

11

What does the Ostwald-Freundlich equation describe?

- the relationshipe between solubility and particle size, in similarity to the Kelvin equation for the condensation of gasses. - smallest particles dissolve first

12

Why is the solubility of irregular particles underestimated by Ostwald - Freundlich?

xx

13

What is supersaturation and how can you prolong this?

- more dissolved than in equilibrium situation. rate nucleation and rate of crystal growth.

14

Describe 5 models of nucleation and growth

LaMer burst nucleation, Ostwald and digestive ripening, coalescence and oriented attachment, finke-watzky 2 step mechanism, intraparticle growth

15

What is nucleation?

- Wikipedia: Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organised structure appears.

16

What are the benefits of using nanosusspensions, and challenges?

- higher bioavailbility, less variability due to food, increased rate of absoprtion, improved absorption of higher doses (tox testing), rapid formulation development ? - agglomeration

17

Mention characteristics of an amorphous state

short-range order (?), low enthalpy of dissolution, metastable, recrystalise at varying T, rel humidity, p and agitation.

18

How can you stabilise an amorphous compound using nanotechnology. Give an example.

- Pb in carbon nanotubes. amorphous compound in a poreous nanomaterial Study with CaCO3; amorpheous, vaterite (poreous), aragonite (non-poreous), calcite (non-poreous) ibuprofen in upsalite

19

Cancer treatment. Why may NPs be a good tool for the passive targetting of tumor tissue?

- poor lymfatic draining, high vascularisation, leaky vessels. EPR effect

20

What are the important physicochemical characteristics of rigid core nanoparticles to enable an optimal bioavailability?

- zeta-potential (neg); size (100-200 nm); hydrophylicity (high) ; these characteristics are good for Enhanced Permeability and Retention.

21

How do you avoid RES (reticuloendothelial system = part of immune response)?

- polyethylene glycol of brush type (vs mushroon type (intermediate PEG density) and pancake type)

22

Describe 2 examples of the use of nanothechnologically-induced hyperthemia.

- photothermal plasmon resonance (Au nanorods); magnetic hyperthermia through Néel or Brownian relaxation.

23

You want to develop a treatment to eradicate a tumor by hyperthermia induced by Au nanorods. At which wavelength should the rods preferably absorb?

NIR (650 - 900 nm) because hemoglobin has minimal absorption below that and water above that.

24

What are today's challenges for the use of nanotechnology in cancer treatment?

- variable EPR effect, rapid clearance, drug resistance, inefficient cargo delivery (?)