2 - Translocation of drugs

Question 1

Bull flow transfer

Answer 1

In blood stream
Chemical properties don’t affect

Question 2

Diffusional transfer

Answer 2

Molecule by molecule over short distance
Chem properties affect (hydrophobicity & aqueous)

Question 3

What does the vascular endothelium do

Answer 3

Acts as a filter
Gaps between them have tightly packed protein matrix

Question 4

What do tight junctions do in the CNS / placenta

Answer 4

Blocks charged (ionised) drugs

Question 5

What drugs do tight junctions let through

Answer 5

Lipid soluble

Question 6

What are pinocytes

Answer 6

When drug from vesicles inside cells to transport macromolecules through membranes

Question 7

Ways in which drugs cross membranes (4)

Answer 7

Diffuse through lipid
Diffuse through aqueous pores
Carrier protein
Pinocytes

Question 8

Name the factors is the permeability coefficient equation (J=P/_\C)

Answer 8

J = no. molecules crossing membrane per unit area in unit time
P = permeability coefficient
/_\C = conc difference over membrane

Question 9

Low lipid solubility =

Answer 9

Polar drug

Question 10

So weak acids pass through the membrane easily

Answer 10

Yes because they are highly protonated

Question 11

What drug increases aspirin absorption

Answer 11

Metoclopramide - increases gastric emptying

Question 12

What drug decreases aspirin absorption

Answer 12

Propantheline

Question 13

Consequences of urinary acidification

Answer 13

Increased excretion of weak acids
Decreased excretion of weak bases (check)

Question 14

Consequences of urinary alkalisation

Answer 14

Increased excretion of weak bases
Decreased excretion of weak acids

Question 15

Increased plasma pH causes extraction of …

Answer 15

weakly acidic drugs from CNS to plasma

Question 16

Decreased plasma pH causes …

Answer 16

accumulation of weakly acidic drugs in the CNS

Question 17

What happens after aspirin overdose
(ETC, RR, CAC)

Answer 17

Inhibits electron transport chain
Increased respiration rate - hyperventilation
Increase citric acid cycle

Urinary alkalisation increases excretion of aspirin

Question 18

What happens to salicylate at normal urinary pH

Answer 18

It is unionised
Can be absorbed back into systemic circulation in nephron

Question 19

What happens to salicylate in alkaline urine

Answer 19

It is charged and reabsorption in reduced

Question 20

What is cisplatin

Answer 20

Anti cancer drug

Question 21

What happens if there’s high exposure to cisplatin

Answer 21

Destruction of mitochondria
Proximal tubular cell death
Organic solutes, Na, H2O loss
Fanconi syndrome

Question 22

How is cisplatin administered without causing death

Answer 22

With an uptake blocker

Question 23

_ is transported by carrier responsible for phenylalanine

Answer 23

Levodopa

Question 24

_ is transported by a carrier for pyrimidines

Answer 24

Flurouracil

Question 25

_’s carrier system is in the jejunum

Answer 25

Iron

Question 26

_ has a vitamin D dependent carrier system

Answer 26

Calcium

Question 27

2 other factors affection distribution / elimination

Answer 27

Binding to plasma proteins
Partition into body fat & other tissues