Distribution

Question 1

What are the factors effecting distribution?

Answer 1

Blood flow and capillaries.

Question 2

How does Blood flow effect the distribution?

Answer 2

1. Some organs get more or less blood e.g kidneys
2. The blood flow cause distribution to the organs
3. If there is a decrease in the blood flow it will lead to a decrease in the distribution e.g Shock in patients.

Question 3

How does capillary permerablity effect the distribution?

Answer 3

1. The splen and liver have a sinusoidal capillary which are leaky
2. Fenested capillaries- have pores allowing it to leak for distribution (High blood flow= high distribution)
3. Continous capillaries- pores are closed so it’s hard for it to be distribution so it needs transports for movement or small hydrophobic drug to move through it so it can be distribution (Decrease in BF= Decrease in distribution)

Question 4

What is protein binding?

Answer 4

1. Normal liver has a certain amount of albumin in the blood and normal kidneys want to maintain the albumin in the blood so it prevent it going to the urine
2. Protein bound drug binds to the albumin, then there are less free drugs so the distribution will be decrease (High protein bound drug= Low free drug= Low distribution)
   3.If there is less albumin less protein bound drugs will bind so there will be more free drugs which will increase distribution to tissue.

Stays in the plasma and it is concentrated in the intracellular fluids

Question 5

What happens in solubility?

Answer 5

1. Albumin cant go across because it is polar, so the free drug can oly go across because it is non-polar (High BF= High distrubtion
2. If there is a drug that is polar, hydrophilic and very large it cant go across so there will be a decrease in distribution.

Question 6

What happens in the volume of distribution (Low)

Answer 6

1. Protein bound drugs bind to albumin, so there will less free drugs
2. The free drugs are very large, polar and hydrophilic so there will be a decrease in the BF and the distribution it will only get the volume of the first place which is 4ml/24ml

It is a example in the Ml

Question 7

What happens in the volume of distribution (Medium)

Answer 7

1. Not many protein bound drugs bind to the albumin, so there will be some small, hydrophobic free drugs( more than the other one)
2. The free drugs will be able to move across from the blood plasma to the interstitial volume 4ml + 8ml+12ml cover two places.

Question 8

What happens in the volume of distribution (High)

Answer 8

1. No protein bound drugs bind to the albumin so there are a lot of hydrophobic, small, non-polar free drugs (Increase in BP= Increase in distribution)
2. The Free drugs are able to go across to the tissue cells 4ml +8ml+12ml= 24ml/24ml Covers all three places