PHAR 230 Lecture Notes - Lecture 6: Aldehyde Dehydrogenase, Blood Proteins, Pharmacokinetics
21 Feb 2017
School
Department
Course
Professor
WEEK 2: PHARMACOKINETICS
PHAR230 LECTURE 6
Pharmacokinetics: study of ADME as a function of time and precisely & quantitatively
Plasma Drug Concentrations: can be used as a therapeutic guide, largely bc the intensity of pharmacologic effect is proportional to
concentration of drug at receptor site, drug in tissue, unbound drug in plasma, total drug in plasma
Goal of pharmacokinetics: devise a dosage regimen that yields optimal drug therapy for indv patient.
One compartment model
• assumes all body tissues and fluids are part of this compartment
• after drug is administered, it is distributed instantaneously
Differentiate between the types of elimination kinetics
Zero Order Kinetics
First Order Kinetics
Deliminated per unit
time
Constant amount of drug
Constant percentage of drug
Drug eliminated by:
Biotransformation
Dependent on transporters
Glomerular filtration (120mL/min)
- drug is freely filtered (not bound to plasma
protein)
- drug is not reabsorbed
Bound to plasma
proteins
Yes
No
Mechanism of
elimination
Saturates
Does’t saturate
Amount of drug
eliminated:
Independent of plasma concentration of
drug
Dependent on plasma concentration of drug
Example
Alcohol
- ethanol is biotransformed in the liver
by ADH and ALDH
- elimination is independent of blood
alcohol conc until blood levels decrease
substantially
Most other drugs
Rate of elimination vs [D]
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Pharmacokinetics: study of adme as a function of time and precisely & quantitatively. Plasma drug concentrations: can be used as a therapeutic guide, largely bc the intensity of pharmacologic effect is proportional to concentration of drug at receptor site, drug in tissue, unbound drug in plasma, total drug in plasma. Goal of pharmacokinetics: devise a dosage regimen that yields optimal drug therapy for indv patient. One compartment model assumes all body tissues and fluids are part of this compartment after drug is administered, it is distributed instantaneously. Alcohol ethanol is biotransformed in the liver by adh and aldh elimination is independent of blood alcohol conc until blood levels decrease substantially. Glomerular filtration (120ml/min) drug is freely filtered (not bound to plasma protein) drug is not reabsorbed. Define and calculate elimination rate constant, volume of distribution, half-life, and clearance for a drug. 11l interstitial fluid) = 42l total: vd = drug in the body / [drug] in blood plasma.
