Chapter 11 - IV Bolus Dose Flashcards
true or false
IV bolus dose undergoes zero order absorption
FALSE - NO ABSORPTION AT ALL!!!!! ALL IS IMMEDIATELY AVAILABLE IN CIRCULATION
true or false
when a drug is given via IV bolus, elimination starts immediately after administration
true
IV bolus dose is eliminated from _____ via ______ order kinetics
the central compartment
1st order
what rate constants do you need to find for a 1 compartment model
ONLY K10
equation for one-compartment model
C=Be ^ -beta(t)
the multi-compartment model differs from the 1 compartment model in several ways, but most predominantly in the ——-
plasma profile
will NOT be a straight line on semi log paper
the first-order plot of plasma conc vs time in a one compartment model results in _______ decline
mono-exponential
does a one compartment model undergo distribution
NO - only elimination
possibly distributes only into very highly perfused tissues – that’s it
true or false
a 1 compartment model (IV) only has ONE first order rate process
TRUE - only elimination
multi-compartment models exhibit ___curve
why?
multi-exponential
because there is more than 1 first order rate process!!! not just elimination
in a multi-compartment model, the nature of the plasma profile depends on….
the number of compartments
2 compartment = bi-exponential curve
3 compartment = tri-exponential curve
true or false
in a 2 compartment model, the plot of plasma concentration vs time will be linear
FALSE - WILL NOT BE. will get a bi-exponential curve
have to feather
WHY does graphing plasma conc vs time of a 2 compartment model result in a bi-exponential curve?
bc of the mixture of the 2 first order processes - distribution and elimination
why must a bi-exponential curve obtained from the graph of a 2 compartment model be resolved into linear segments?
has to be done to calculate the PK parameters
2 other terms for “feathering”
curve-stripping
method of residuals
the terminal portion of a bi-exponential curve represents what
the elimination of the drug from the body
the y-intercept of the B line is…
the rate constant of the B line is…
B – Co
the rate constant of the B line is Beta
2 straight lines means _______ compartment model
2
when the bi-exponential curve is feathered, it generates _____ y-intercepts
what are they
2
A and B
also 2 rate constants - alpha and beta
2 compartment model formula
C = Be ^-beta(t) + Ae^-alpha(t)
**note - have to know what eaach rate constant is - he won’t tell on exam
ie - k10 is elimination constant
k12 is distribution from central compartment to tissue, etc
you got this !!!!!!!!!!!!!!
true or false
in a 2 compartment model, elimination only takes place from the central compartment
TRUE
what is the rate constant for the elimination phase
beta
what is the rate constant for the distributive phase
alpha
true or false
in a 2 compartment model, the concentration in the tissue is NOT THE SAME as the concentration in the central compartment
true
at what point will only elimination predominate
when distribution reaches equivalence
true or false
beta is always a higher value than alpha
FALSE - alpha is always higher than beta
if beta is a VERY HIGH VALUE, what does this mean
there is no distribution (accumulation) at all. this is a 1 compartment model
what is P?
indicates 3 compartment model
the y-intercept of the first order rate process of shallow distributive phase process
what is pi
indicates 3 compartment model
hybrid rate constant for shallow distributive phase
true or false
pi is not a hybrid rate constant
false - it is
true or false
pi is the hybrid rate constant for the deep distributive phase
FALSE - shallow
alpha is deep
true or false
in the 3 compartment model, A is the y-intercept for the deep distributive phase
TRUE
true or false
for IV 3 compartment model, Beta is the hybrid rate constant for the elimination phase
true - this doesnt change
true or false
in the 3 compartment model, there are theoretically 3 separate tissue types that the drug distributes to
FALSE - 2 different ones
central compartment + 2 tissue compartments = 3 total compartments
how many rate constants are there in the 3 compartment model IV
5 actual (K10, K12, K21, K13, K31)
3 hybrid (alpha, beta, pi)
in the 3 compartment IV model, state what each of the 5 rate constants are
k10 - elimination rate constant
k12 - rate constant from central compartment to SHALLOW tissue
k21 - rate constant from SHALLOW tissue to the central compartment
k13 - rate constant from the central compartment to the DEEP tissue
k31 - rate constant from the DEEP tissue to the central compartment
true or false
in the 3 compartment model, elimination of the drug occurs in several places
FALSE - only from the central compartment
true or false
in the 3 compartment model, k13 is always higher than k12
FALSE - k12 is higher
k12 is from the central compartment to the SHALLOW tissue—– this occurs faster than the deep tissue
what is Vc
apparent volume of distribution of the central compartment
Vc=…..
dose/Co
Co = all of the y-intercepts added together (# varies depending on what model. will be 2 for 2 compartment model and 3 for 3 compartment model)
true or false
shallow tissue reaches equivalence FASTER than the deep tissue
true
true or false
a lot of drugs follow the 3 compartment model
FALSE - not a lot at all
most are adequately described by a 2 compartment model. 90% accuracy is all we need
raw date - B line =…..
pure distribution (A line)
true or false
in a 3 compartment model, alpha is a higher value than pi
FALSE - pi is a higher value than alpha. shallow tissue reaches equivalence first
A first-order plot of plasma concentration versus time in a three-compartment model results in what kind of curve?
tri-exponential
which will have a steeper initial decline in concentration from the central compartment and why — 2 compartment model or 3 compartment model?
3 compartment model because the drug is leaving the central compartment in 3 ways rather than 2—
-elimination
-distribution to deep tissue
-distribution to shallow tissue
how many featherings are needed for a 3 compartment model
2
in a plot, is concentraion x or is time x
y = concentration
x = time
in an IV 3 compartment model, what does the 1st feathering remove
removes the effect of elimination
in an IV 3 compartment model, what does the 2nd feathering remove
removes the effect of the deep tissue
the residuals generated (triangle line) represent pure distribution to shallow tissue
in an IV 3 compartment model, which points should be used to find B, P, and A
for B - use last 2 points. pure elimination
for A - use points somewhat in the middle. pure deep distribution
for P - use 1st 2 points. pure shallow distribution
true or false
in an IV 3 compartment model, from the first feathering, we will get A and alpha
true
from the 2nd feathering we will get P and pi
to obtain A, alpha values in the IV 3 compartment model, what points do you use
the last 2 points that were NOT on the B line
this is guaranteed deep distribution
at what point is there just PURE ELIMINATION in an IV 3 compartment model
when the deep tissue, shallow tissue, and central compartment have all reached equivalence
rank the following according to how big they are
alpha
beta
pi
pi is largest
then alpha
beta is smallest
true or false
k12 has a higher transfer rate than k13
true
