Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
18 Cards in this Set
- Front
- Back
|
one compartment model: description
the plasma drug concentration can be expressed in various forms |
- free drug concentration
- total (free + protein bound) drug concentration |
|
|
volume of distribution I
Vdf |
defined on the basis of the free drug concentration
given by eq 13 |
|
|
volume of distribution I
Vd |
in practice, is most often defined on the basis of the total plasma drug concentration (free and protein bound).
|
|
|
what is the relationship between Vd and Vdf?
|
Vdf = n/ca and vd = n/cp
|
|
|
volume of distribution II
the aqueous compartments in the numerator include plasma, which can be separated |
see slide
|
|
|
volume of distribution III
eq 19 |
see slide
|
|
|
Vd and processes in plasma and tissues
Vd is: |
the volume of the body corrected for
-membrane accumulation: characterized by the membrane/water partition coefficient P - protein binding that is characterized by the average association constant K and the protein concentration p in plasma (p) and tissues (i) see slide |
|
|
Vd and body volume
if the drug is not bound to proteins |
Kp = 0, Ki = 0
|
|
|
Vd and the body volume
if the drug is accumulated in the membranes |
P = 1
|
|
|
Vd is equal to the volume of the body (biosystem)
|
true
Vd = Vp + Vm + sum aq Vi see slide |
|
|
Vd and plasma volume
If the drug is strongly bound to plasma proteins and practically absent in tissues: |
Kp * Pp >> Ki * pi
Kp * Pp >> (P * Vm + sum aq Vi) |
|
|
Vd is equal to the volume of plasma
|
true
Vd= Vp |
|
|
Vd and binding/accumulation
the volume of distribution is increased by: |
stronger binding to tissue proteins and membranes (no upper limit)
|
|
|
Vd and binding/accumulation
the volume of distribution is decreased by: |
stronger binding to plasma proteins, up to the limiting value of the volume of plasma
|
|
|
typical values of Vd
|
see slide and notes under
|
|
|
Vd and fractions unbound I and II and III
|
see slide
|
|
|
Vd and accumulation in individual tissues I
|
see slide
|
|
|
Vd and accumulation in individual tissues II and III
** important ** |
see slide
|
