weeks 1-3 Flashcards
1
Q
Clearance
A
efficiency of irreversible elimination
- often relative to liver blood flow (90 L/ hour) or Kidney blood flow ( 66 L/ hour)
- proportionality factor used to determine the rate of elimination
2
Q
Volume of distribution
A
- proportionality factor which relates drug concentration to dose
- large volume indicated higher deposition into adipose tissue and other bodily compartments
- considered large if > body weight
3
Q
Assumptions of the 1 compartment model
A
- body acts as a single uniform compartment
- drug distributes instantly
4
Q
Two-compartment model
A
- drug instantly distributes to central compartment and more slowly to peripheral compartment(s)
- elimination occurs through central compartments
5
Q
Acidic and neutral drug binding
A
- primarily bind to to albumin
6
Q
basic drug binding
A
- bind to the acidic alpha 1 acid glycoprotein
7
Q
relative concentrations of plasma proteins
A
albumin > alpha 1 acid glycoprotein > lipoproteins > globulin
8
Q
Impact of PPB
A
- prolongs duration of drug action
- increases amount of drug necessary for therapeutic effect
- as binding is non specific DDI may occur
9
Q
Excretion
A
- removal of unchanged drug from the body
- major pathway = renal
- minor pathways = bile, sweat saliva etc
10
Q
Biotransformation
A
- Conversion to metabolites which are then excreted from the body
- most commonly occurs in the liver
11
Q
Total bodily clearance
A
= CLr + CLh + CLother
=> total K = Kr + Kh + Kot
12
Q
Requirements for renal clearance
A
- Water soluble
- low molecular weight
- biotransformed into more soluble metabolites in the liver
13
Q
Determinants of renal filtration
A
- Size, large molecules do not pass through the glomerulus
- Fu, bound drugs are not filtered
14
Q
Determinants of reabsorption
A
- primarily passive diffusion
=> lipophilicity, Pka concentration gradient between renal urine and plasma - existence of active transporting system
15
Q
Determinants of secretion
A
- Occurs via active transport
