Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacokinetics > Oral Absorption > Flashcards

Oral Absorption Flashcards

1
Q

What are the 3 definitions of absorption?

A
  1. Absorption occurs when drug reaches the systemic circulation
  2. When drug reaches the portal veins blood stream
  3. Drug is assumed to be absorbed when it leaves the lumen and crosses the apical membrane of the enterocytes lining the intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the factors that affect drug absorption?

A
  1. Physiochemical properties of drug and environment of small intestine
  2. Dosage form
  3. Anatomy and physiology of absorption site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the properties of the absorption site an can effect drug absorption?

A
  1. SA or GIT
  2. Stomach emptying rate
  3. GI motility
  4. Blood flow to absorption site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the studies of absorption kinetics?

A
  1. Top-down
  2. Bottom-up
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the difference between top-down and bottom-up?

A

TD: Based on observed clinical data
BU: Based on the broader understanding of the human body and its mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the top-down approach?

A
  1. Based on compartmental models
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the bottom-up approach?

A
  1. Small elements of system are defined in great detail
  2. Smaller elements are combined into subsystems, and systems to describe overall process
  3. More complicated approach with many variables
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the goal of top-down and bottom-up methods?

A

To make plausible physiologic predictions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the PK of drug absorption?

A
  1. Can be 1st or 0
  2. Rate of drug amount is dependent of rates of elimination and absorption
  3. Net rate of drug accumulation is body is equal to the rate of absorption less than elimination regardless of 0 or 1st order
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the equation for PK drug absorption?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the absorption phase?

A
  1. Rate of drug absorption is greater than the rate of drug elimination
  2. Elimination phase still occurring during absorption phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the peak-drug concentration?

A
  1. Rate of drug absorption equals the rate of drug elimination
  2. No net change in the amount of drug in the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is post-absorption phase?

A
  1. Immediately after peak drug absorption
  2. Some drug is still absorbed
  3. Rate of drug elimination is faster than rate of absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the elimination phase?

A
  1. Drug at the absorption site becomes deplete
  2. The rate of drug absorption approaches 0
  3. Curve represents elimination only
  4. First order
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Identify the phases of drug absorption

A

A: Absoprtion
B: Peak drug concentration
C: Post absorption
D: Elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is are the factors that effect the rate of absorption?

A
  1. Drug dissolution
  2. GI motility
  3. Blood flow
  4. Drug transport across membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the difference between o and 1st order absorption?

A

0: controlled release products or saturable absorption processes
1: Immediate release products

18
Q

What is ka useful for?

A

Designing multiple dose regimens

19
Q

What is k and ka useful for?

A

Determining peak and trough concentration in multiple dosing

20
Q

What is the equation associated with 0-order input, 1st order output

A
21
Q

What equation describes 1st order absorption (just absorption)?

A
22
Q

What equation describes 1st order absorption (just elimination)?

A
23
Q

What is equation that describe both 1st order absorption and elimination?

A
24
Q

What is tax?

A

Time to reach peak concentration

25
Q

What is Cmax?

A

Peak concentration following a single dose

26
Q

What factors is tmax independent and dependent on?

A

I: Dose
D: rate constant for ka and k

27
Q

Identify the properties of Cmax?

A
  1. Rate of drug absorbed is equal to the rate of drug eliminated.
  2. Net rate of concentration change is equal to zero
  3. Directly proportional to Dose and F.
28
Q

How do we find tmax?

A
29
Q

How do we find Cmax?

A
30
Q

What are the intercept methods to find k?

A
  1. Plasma concentration
  2. Amount excreted in urine
31
Q

What is the equation for the elimination phase?

A
32
Q

How do we get k?

A

Find in by the elimination phase slope

33
Q

What is ka negative?

A

Drug is leaving the GIT and eliminating into body

34
Q

What is lag time?

A

The time delay prior to the commencement of first-order drug absorption

35
Q

What might cause lag in absoprtion?

A
  1. Changes in Gi motility
  2. Opiods
  3. Metoclopramide
  4. Natural aging: constipation
36
Q

When would a flip-flop or k and ka occur?

A

Drugs with fast elimination (k>ka)

37
Q

What are the effects of Ka on Cmax,Tmax, AUC?

A

Increased Ka: Decrease tmax, Increase Cmax, AUC unchanged

38
Q

Effects of K on Cmax, Tmax, and AUC?

A

Increased K: Decreased tmax, Cmax, AUC

39
Q

What are the effects of flip-flop Ka>K?

A

Increase ka and decreased k: tmax unchanged, increase Cmax and AUC

40
Q

What is Wagner-Nelson used for?

A

1COM model

41
Q

What is Loo-Riegleman used for?

A

2COM model

Pharmacokinetics (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions