PK/BD/BE/PD Studies Flashcards
Pharmacokinetics
Effect of the body on a drug;
Or, the way the body handles a drug (absorption, distribution, metabolism, elimination etc.)
Pharmacodynamics
- Effect of a drug on the body;
Or, the relationship of drug concentration and biologic (physiological or biochemical) effect.
Absorption is
The point of the devivery
What affects drug absorption
Size and structure of drug
Disintegration of drug
Dissolution of drug
Charged (ionized) nature of the drug
Conditions and function of the absorptive surface (transporters)
Attack of the digestive flora and digestive enzymes
Concentration and salt form
Factors Affecting Drug Metabolism
Age, sex
disease states
blood flow to metabolizing organ
diet, smoking, environmentla factors
genetic polymorphismis
drug interactions
As a drug is broken down, it may be changed in a way that
Decreases its desired action
Increases its desired action
Increases undesired actions
Drug excretionis the
removal ofdrugsfrom the body, either asa metabolite or unchanged drug. There are many different routes ofexcretion, including urine, bile, sweat, saliva, tears, milk, and stool.
By far, the most important excretory organs are the kidney and liver.
How a drug acts on target sites of action in the body, referred to as
pharmacodynamics.
is a medical term that describes how a medication works in the body.
mechanism of action
Example: A common laxative like magnesium citrate attracts and binds with water.
The mechanism of action for this medication is it pulls water into the bowel, which softens stool and increases the likelihood of a bowel movement.
Anagonistbinds
tightly to a receptor to produce a desired effect.
Anantagonist
competes with other molecules and blocks a specific action or response at a receptor site.
inhibitors
Many target specific enzymes for a desired effect.
Example: Monoamine oxidase inhibitors (MAOIs) are prescribed as antidepressants because they block monoamine oxidase, the enzyme that breaks down serotonin and dopamine. This blockage increases the concentration of serotonin and dopamine in the central nervous system and increases a client’s feelings of pleasure.
How to measure PK (PHARMACOKINETIC)
Plasma level vs. Time studies
Urinary Excretion Studies
Assay(s) needed
How to measure PD (Pharmacodynamic Method)
Acute Pharmacologic Response
Therapeutic Response
Why is PK/PD important?
Bioavailability
A measurement of the rate and extent to which a therapeutically active chemical is absorbed from a drug product into the systemic circulation and becomes available at the site of action.
Bioavailability is
A blood concentration-time curve (a series of measurements over time) shows the release of the active ingredient from the drug and its absorption from the GI tract,
Can also impact metabolism, distribution, and elimination
Two medicinal products arecalled bioequivalentif
bioavailability (rate and extent) after administration (at the same(molar) dose are “similar” to such degree that their effects, with respect to both efficacy and safety, will be essentially the same
FDA Requirements for Bioequivalence
Product A is bioequivalent to the reference drug; its 90% confidence interval of the AUC falls within 80% to 125% of the reference drug
Product B is not bioequivalent to the reference drug; its 90% confidence interval of the AUC falls outside of 80% to 125% of the reference drug
PK/adme is what is
happenidn to the drug
PD is what is happenin
to the body
BA is
the drug getting to where it needs to be in sufficient amoutns
BE IS
there a generic version availavle
