Lecture 1 Flashcards
Pharmacokinetics
- study of kinetics of ADME of the drugs and their corresponding pharmacologic therapeutic, or toxic response in man and animals
- describes what body does to drugs
- path the durg takes in the body
Biopharmaceutics
- study of factors influencing bioavailabity of a drug in man or animal and the use of this info to optimize pharmacological and therapeutic acitivity of drug products
- chemical nature of drug
- excipients
- method of manufacturing
- physiochemical properties
Pharmacodynamics
- Describes what the drug does to the body
- Receptor binding
- Post-receptor effects
- Intensity and time-course of a drug’s effect
Intravascular routes
- Intravenous
- Intra-arterial
- no absorption phase
- immediate onset of action
- entire administered dose is available to produce pharmacological effects
- this rouse is used more often in life-threatening situations
- adverse reactions are difficult to reverse or control; accuracy in calculations and administration of drug dose is very critcal
Extravascular routes
- oral administration (tablet, capsule, suspension, etc.)
- intramuscular administration (solution and suspension)
- subcutaneous administration (solution and suspension)
- sublingual or buccal administration (tablet)
- rectal administration (suppository and enema)
- transdermal drug delivery systems (patch)
- inhalation (metered dose inhaler).
- An absorption phase is present.
- The onset of action is determined by factors such as formulation and type of dosage form, route of administration, physicochemical properties of drugs and other physiological variables.
- The entire administered dose of a drug may not always reach the general circulation (i.e., incomplete absorption).
Absorption
Absorption is defined as the process by which a drug proceeds from the site of administration to the site of measurement (usually blood, plasma or serum).
Distribution
- reversible transfer of drug to and from the site of measurement (usually blood or plasma).
- Any drug that leaves the site of measurement and does not return has undergone elimination.
The rate and extent of drug distribution is determined by:
- how well the tissues and/or organs are perfused with blood
- The binding of drug to plasma proteins and tissue components
- The permeability of tissue membranes to the drug molecule.
Metabolism
a conversion of one chemical species to another chemical species
Elimination
Elimination is the irreversible loss of drug from the site of measurement (blood, serum, plasma). Elimination of drugs occur by one or both of:
- metabolism
- excretion.
Excretion
- Excretion is defined as the irreversible loss of a drug in a chemically unchanged or unaltered form.
- Kidney: removal of a drug in a chemically unaltered or unchanged form (i.e., excretion) as well as for metabolites.
- The lungs: substances of high vapor pressure (i.e., gaseous anesthetics, alcohol, etc.).
- Durgs can also be excreted via milk glands
Disposition
disposition is defined as all the processes that occur subsequent to the absorption of the drug.
= distribution and elimination.
Peak plasma levels
Related to dose, absorption and elimination rate constant ( k)
AUC ( area under the curve)
Related to amount of drug absorbed
