Module 3 stuff i dont know

Question 1

absorption

Answer 1

passage of drug from site of administration to plasma

Question 2

acids and bases absorption

Answer 2

weak acids and bases are easily absorbed

strong acids and bases are poorly absorbed (bc mostly/ fully ionised)

penicillin = acid labile = unstable in low pH of stomach

Question 3

Absorption from GI tract

Answer 3

Stomach

Duodenum
Jejunum
Ileum

Colon
Rectum

Question 4

Absorption from the GI tract is dependent on

Answer 4

Concentration gradient
Lipophilicity (R value)
Blood flow to site of absorption
Surface area ! (most absorption occurs in small intestine bc of large surface area)
Formulation
GI tract contents
Gut motility

Question 5

basic principle of metabolism

Answer 5

the body sees all drugs as foreign and wants to get them out asap without causing harm - hence metabolism

Question 6

two major types of enzymatic reactions

Answer 6

phase 1
- functionalisation (makes more reactive)
- catabolic reaction
e.g. oxidation, reduction, hydrolysis
- liver

phase 2
- conjugation
- anabolic reaction
e.g. add water soluble moiety to a drug
- liver, lungs, kidney

Question 7

aspirin in an enzymatic reaction

Answer 7

phase 1
- drug

derivative
- salicylic acid

phase 2 - conjugate
- glucuronide

Question 8

goal of metabolism

Answer 8

get drug out of body
reduce risk of toxicity

• reduce reactivity

BUT it has to become more reactive before it becomes less reactive

Question 9

Phase 1

Answer 9

Cytochrome P450

Heme proteins that use Fe3+ at active site
- happening inside cell (endo retic)
- mostly in liver
- wide range of substrates
- reaction requires oxygen, NADPH, and cytochrome p450 reductase

Question 10

the activity of each enzyme varies

Answer 10

1. induction
2. inhibition
3. genetic variation

Question 11

1. induction of CYPs

Answer 11

…

Question 12

excretion

Answer 12

3 main ways:
- urine
- poop
- sweat (maybe milk)
- air