Bioavailability Flashcards
Generic drugs are ____ and ____ alternatives to brand name prescriptions
safe and effective
T/F One of the primary ways physicians can practice cost effective prescribing is by offering patients a generic medicine when one is available
TRUE
When can a generic be created?
once the patent expires on the innovator
What are the applications of bioavailability and bioequivalence studies? (5)
- determine the effect of various formulations
- determine food effects
- evaluate the effect of age, disease, etc
- assess route of administration effect or first pass effect
- ANDA
ANDA
abbreviated new drug application–> used for the approval of generic drugs
The goal of bioavailability studies is to….
control all the variables except for the one you are testing
bioequivalent= similar
bioavailability
Steps for bioavailability study? (5)
- recruit healthy volunteers
- administer the drugs to volunteers
- Collect samples of biological fluids (typically blood)
- Analyze
- Draw graph
availability
- measure of relative amount absorbed (looking at ratios of AUC)
- range from 0 to 1
______ compares AUC to an IV DOSE
absolute availability
_______ compares AUC to a reference
relative availability
Which availability is used for ANDA?
relative
How can you calculate the total amount absorbed?
absolute availability
A test oral formulation has the same area under the plasma concentration-time curve as the reference formulation. This means that the two formulations…
A) are bioequivalent by definition- related to AUC
B) deliver the same total amount of drug to the body but are not necessarily bioequivalent
C) are bioequivalent if they both meet USP dissolution standards
D) deliver the same total amount of drug to the body and are, therefore, bioequivalent
E) have the same rate of absorption
B) deliver the same total amount of drug to the body but are not necessarily bioequivalent because the rate may be different (if the rate is dif. Then they may not be considered bioequivalent)
excretion vs. metabolism
excretion: drug is unchanged
metabolism: drug is converted to some other form
urinary excretion studies
graph the cumulative excretion
T/F Urinary Excretion studies increase and then decrease.
FALSE: starts at zero–> increases until it plates–> It NEVER decreases because it is cumulative
When a cumulative excretion graph plateaus, what does this mean?
all the drug is out of the body; time to plateau is related to the rate of absorption
Potassium Penicillin G was given IV to volunteers, 80% of a 500mg dose was recovered unchanged in the urine. 280 mg was recovered in urine when the same dose was given IM to the same subjects. Calculate the availability of the IM injection. What type of availability is this?
F = 280/400 = 0.70; absolute