ADME1: Lecture 7 Flashcards Preview

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Flashcards in ADME1: Lecture 7 Deck (11):
1

What are the major organs involved in ADME?

1. GI Tract(Absorption) 2. Liver(Metabolism) 3. Kidney(Excretion) 4. Lungs( Absorption and excretion of volatile anaesthetic gases)

2

How does the biological membrane impact on drugs?

Small, uncharged and lipid soluble drugs are distributed faster than ionised, bulky and lipid insoluble drugs.

3

What are the 4 mechanisms of transport across the membrane?

1. Transcellular diffusion 2.Facilitated diffusion 3. Active transport 4. Endocytosis

4

What are the properties of passive diffusion?

-Most important mechanism for lipid soluble drugs(ie non-polar) - Concentration gradient is the driving force -No energy is required

5

What are the properties of facilitated diffusion?

-Depends on a carrier protein -Depends on concentration gradient -No energy required -Usual substrates=sugars and amino acids

6

What are the properties of active transport?

- can proceed against a conc. gradient -Requires energy - can become saturated -Organs= Liver, Kidney, blood-brain barrier, gut epithelium

7

What does active transport achieve?

1 Accumulates compounds essential for growth 2. Removes waste products 3. Protects against toxins

8

What are the main properties of Endocytosis?

-Internalisation of large molecules -MW>1000 -3 steps involved 1.Substrate binds to receptor 2.Invagination of receptor-substrate complex 3. Budding off and delivery of vesicle into cell.

9

What does filtration help with?

For drugs that cannot pass through cells to cross biological membranes

10

Where does filtration occur?

Blood capillaries Glomerular capillaries (Kidney)= extremely porous which allow passage of all plasma constituents except >30,000.

11

Summarise the path of drug deposition in the body?

 

Drug dosage⇒ Free drug concentration in exracellular water⇒Metabolism, Binding to proteins and storage in tissues, AND Biliary and Renal excretion⇒Drug conc at site of action(small)⇒Receptor occupancy⇒Intensity of pharmacological effect