Multiexponential PK Flashcards
(13 cards)
What is the primary characteristic of the Two Compartment Model in multiexponential pharmacokinetics?
Distribution to some parts of the space takes time, meaning distribution is NOT instantaneous.
This model illustrates how drug distribution and elimination occur over time, with equilibrium not being immediate.
What happens to the volume of distribution in the Two Compartment Model until equilibrium is reached?
The volume of distribution increases until equilibrium between ‘central’ and ‘tissue’ is reached.
This reflects the time-dependent nature of drug distribution in the body.
In the Two Compartment Model, how does the decline in plasma drug concentration occur initially?
Initially, the decline is due to both elimination and distribution.
This dual decline phase is important for understanding early pharmacokinetic behavior.
What is the characteristic of the plasma drug concentration decline later in the Two Compartment Model?
Later, the decline is only by elimination.
This indicates that distribution effects diminish over time.
What type of decline is observed in multiexponential pharmacokinetics?
Bi-exponential decline.
This indicates two phases of drug concentration decline in the plasma.
How should the curve in multiexponential pharmacokinetics be treated for calculations?
Treat the curve as two straight lines and do calculations separately, then add them together.
This approach simplifies the analysis of complex pharmacokinetic profiles.
What does the equation Cp = A e^(-at) + B e^(-Bt) represent?
It represents the plasma concentration over time in multiexponential pharmacokinetics with components for the initial sharp drop (alpha) and the slower curve (beta).
This equation is fundamental for modeling drug concentration in the body.
What are the two half-lives in multiexponential pharmacokinetics?
Alpha half-life and beta half-life.
The alpha half-life is associated with the initial distribution phase, while the beta half-life is associated with elimination.
Which half-life is considered more important in multiexponential pharmacokinetics?
Beta half-life is MORE IMPORTANT because it is longer.
The beta half-life reflects the elimination phase, which is crucial for dosing regimens.
What is the formula for the elimination constant (Kel) in multiexponential pharmacokinetics?
Kel = aß / k21.
This formula relates the rates of elimination and distribution between compartments.
What does Vc represent in pharmacokinetics?
Vc = Dose / AUC.
Vc is the volume of distribution in the central compartment.
What is the formula for beta volume of distribution (Vd beta)?
Vd beta = Clearance / beta.
This calculation helps in understanding drug distribution during the elimination phase.
What does Vss represent in pharmacokinetics?
Vss = Xss / Css.
Vss is the volume of distribution at steady state, important for understanding drug accumulation.
