Toxicokinetics Flashcards
Toxicokinetics is the quantitative study of…
ADME - Absorption, Distribution, Metabolism and Excretion
What is the relevance of 10% blood volume for AUC studies?
This is the upper limit of blood volume that should be drawn across the study to limit physiological impacts from excessive blood draws.
Zero order rates applies to what type of absorption?
Zero order absorption relates to fixed amounts of chemical absorbed over time, and frequently describes dietary exposure where transporters are saturate. This is not proportional.
K sub “a” refers to?
The absorption rate (coefficient) of a chemical
A high Vd value implies what?
The chemical preferentially accumulates in tissues instead of the blood compartment.
A small Vd (<1) value implies what?
Preferential accumulation in the blood compartment over the tissue compartment.
“Clearance” is expressed as?
The unit of body fluid (mL) cleaned of a toxicant per unit of time (hours or minutes).
A clearance of 0.5 L/h implies what?
0.5 L/h implies that 0.5 L or 500 mL of bodily fluid is cleaned of a toxicant per hour.
Clearance (CL) is equal to what?
CL = Dose / integral of AUC
How does free fraction (f) relate to the Vd?
Free fraction reflects the amount of unbound chemical in in the plasma where as the Vd reflects the total amount of toxicant in the blood/plasma versus tissue. Depending on the Vd and f, a chemical may be abundant in plasma but tightly bound to plasma proteins and unavailable if the f is very low.
What is the equation for elimination half life? Hint, used it for PFAS risk assessment and RfD development
t (sub 1/2) = (0.693 * Vd)/CL
or (Ln2*Vd)/CL
