E1 L4: Oral Dosing

Question 1

3 routes of admin

Answer 1

IV bolus
Iv infusion
Extravascular

Question 2

Peak concentration at CP0
Measure of drug in the veins

Answer 2

IV bolus

Question 3

Drug accumulates in the body until it reaches a plateau

Answer 3

IV infusion

Question 4

Outside of the vasculature
Anywhere outside of vein
oral absorption
Intransal, patch

Answer 4

Extravascular

Question 5

Why extravascular graph looks different

Answer 5

All of the drug is going into GI tract but that is not where we measure - measure in blood - some is lost in transit

Question 6

CMax points for IV bolus, IV infusion and Extravascular

Answer 6

IVB - C0
IV I - plateau
Ex: peak

Question 7

Tmax points for IV bolus, IV infusion and Extravascular

Answer 7

IV B - 0
IV infusion - (where plateau ends
Ex: Where peak stops

Question 8

AUC: bigger the area…

Answer 8

Greater exposure to drug over time

Question 9

Advantage of oral drug admin

Answer 9

Ease of admin

Question 10

Disadvantages of oral drug admin

Answer 10

Source/variability of response
Takes time for drug to enter systemic circulation following admin
Some drug may be lost during the absorption process

Question 11

Two types of oral drug products

Answer 11

Immediate release and modified release

Question 12

Immediate release products

Answer 12

tablets and capsules (most common)
Liquids: syrups, elixirs, suspensions, and emulsions

Question 13

Modified release products:

Answer 13

ER:
controlled release - approximates zero order release
Constant drug release over time
Sustained-release: maintains drug release but not at a constant rate
Delayed Release:
common examples is enteric-coated aspirin

Question 14

Oral drug formulations

Answer 14

Immediate release
Sustained release
Controlled release
Delayed release

Question 15

If the same dose is given in three different formulations, will they all have the same AUC

Answer 15

yes

Question 16

Comparison of oral admin with IV admin

Answer 16

Absorption delays the magnitude of the peak compared with that seen following an equal IV bolus dose

Question 17

IV bolus is - order elimination

Answer 17

1st order

Question 18

Iv infusion is - order elimination

Answer 18

0 order

Question 19

Oral admin is - order of elimination

Answer 19

First order (amount in absorption compartment changes over time)

Question 20

Absorption occurring faster than elimination =

Answer 20

Net concentration

Question 21

Ka * Abs > kel * A

Answer 21

Absorption phase

Question 22

Ka * Aabs = Kel * A

Answer 22

Cmax

Question 23

Ka * Aabs < Kel *A

Answer 23

Post absorption phase

Question 24

T/F: if Ka < kel, absorption rate limits elimination

Answer 24

True
Rate of absorption is controlling rate of elimination of drug

Question 25

Only way to eliminate faster

Answer 25

Increase Ka (flip-flop kinetics)

Question 26

tlag def

Answer 26

Absorption of a drug after a single oral dose may not start immediately - can be anywhere from minutes to hours

Question 27

Complexities that alter tlag:

Answer 27

Disintegration/dissolution
GI motility
Blood flow
Drug transport

Question 28

Why is cmax lower for oral dose?

Answer 28

Loss of drug during absoprtion

Question 29

Fraction of drug absorbed (F)

Answer 29

Portion of dose administered that reaches systemic circulation

Question 30

Factors that can affect F

Answer 30

Dissolution
Gut wall permeation
Active transport
Metabolism
Biliary excretion

Question 31

FDA definition of bioavailability

Answer 31

“The rate and extent to which the active ingredient or active moiety is absorbed from a drug and becomes available at the site of action

Question 32

F = Bioavailability

Answer 32

NO - NOT a measure of the rate of absorption (only extent)

Question 33

Fraction of drug absorbed equation (absolute bioavailability)

Answer 33

F =(AUC oral)/(Dose oral)/ (AUC IV)/ (Dose IV)