[5] Biotrans 1 - 2.5

Question 1

Mechanism by which the body terminates the
action of some drugs.

(or eliminate them from our system)

Answer 1

DRUG METABOLISM

Question 2

In some cases, it serves to activate “prodrugs”

(they are inactive so they need to be activated)

Answer 2

DRUG METABOLISM

Question 3

Inactive drugs

Answer 3

PRODRUGS

Question 4

PATHWAYS TO DRUG METABOLISM

(readily excreted by the kidneys)
1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

Answer 4

1. Active —– inactive

Question 5

Administered to our body. Requires activation to our metabolic processes

Answer 5

PRODRUGS

Question 6

THREE POSSIBLE PATHWAYS TO DRUG METABOLISM

Answer 6

1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

Question 7

PATHWAYS TO DRUG METABOLISM

(a drug may be administered to our body which is already active)
1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

meaning that they are able to interact with the receptors.

Answer 7

1. Active —– inactive

Question 8

Receptor binding requires specification as
to the structure of our drug

1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

some may need to add water
soluble groups or even some may
require unmasking of hydrophobic
or hydrophilic components of the
drug, so it will fit into the receptor.

Answer 8

1. Active —– inactive

NOTE: So as we have said, some drugs are
already active when they are given to our
body and would have already reacted to the
receptors. Now what our body will do is to
inactivate them and they could be readily
excreted thru our kidneys.

Question 9

PATHWAYS TO DRUG METABOLISM

other drugs are actually administered as active and when they are broken down

1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

they would also have active metabolites

for these types of drugs, the duration of
action would somehow be longer as
opposed to the first mechanism

Answer 9

2. Active —– active metabolites

Question 10

PATHWAYS TO DRUG METABOLISM

drug which is a prodrug - meaning that they are inactive

1. Active —– inactive
2. Active —– active metabolites
3. Inactive — active (Prodrug)

Answer 10

3. Inactive — active (Prodrug)

NOTE: some drugs that will not pass thru
the liver

Question 11

PHASES OF METABOLIC ACTIONS

Non - synthetic reactions

Answer 11

PHASE 1

Question 11

PHASES OF METABOLIC ACTIONS

Converts the parent drug to a more polar conjugate (water soluble) or more reactive product

more polar = more water soluble = more active

They intend to make a parent drug
whether active or inactive, more polar

Answer 11

PHASE 1

Question 12

PHASES OF METABOLIC ACTIONS

1. OXIDATION
2. REDUCTION
3. DEAMINATION
4. HYDROLYSIS

These are what phase of metabolic actions:

Answer 12

Phase 1

Question 12

PHASES OF METABOLIC ACTIONS

Introducing/inserting/unmasking a polar functional group. These include OH, SH, NH2 - hydroxyl, sulfidril, as well as amino group

These functional groups when they are
already present in our drug can be
unmasked, kung hindi naman they can be
inserted to the parent drug.

Answer 12

PHASE 1

NOTE: PHASE 1 normally precedes phase 2, but of
course we have some exceptions.

Question 13

PHASES OF METABOLIC ACTIONS

Synthetic reactions

Answer 13

PHASE II

Question 14

PHASES OF METABOLIC ACTIONS

Endogenous substrate is conjugated to the parent drug to make it more polar

Mas madali maeliminate because polar. Substrate coming from our metabolic reaction to the metabolic drug

Answer 14

PHASE II

intention: to make it polar for it to be
eliminated easier/readily

Question 15

PHASES OF METABOLIC ACTIONS

1. Glucuronidation - glucuronic acid - ADDITION of glucuronic acid
2. Acetylation-acetyl COA - Adding acetyl group from acetyl coA
3. Sulfation
4. Methylation
5. Glycine conjugation-glycine
6. Glutathione conjugation – Addition of glutathione
7. H2O conjugation

These are what phase of metabolic actions:

Answer 15

phase II

Question 16

Common Route:
PHASE I ———- PHASE II (most drugs)
PHASE II ——— PHASE I (other drugs)

Answer 16

PHASE I ———- PHASE II (most drugs)

Question 17

Isoniazid Acetylation ——- hydrolysis:
PHASE I ———- PHASE II (most drugs)
PHASE II ——— PHASE I (other drugs)

Answer 17

PHASE II ——— PHASE I (other drugs)

Question 18

Recall: drugs which become (non-polar/polar)
are eliminated through the urine.

Answer 18

Polar

Question 19

drugs that can not turn polar would be excreted through our ______.

Answer 19

biliary system.