Lecture 3

Question 1

C max

Answer 1

maximum concentration of drug in blood following single dose

Question 2

Tmax

Answer 2

time the maximum concentration is reached

Question 3

Area under the curve

Answer 3

plot of centration of drug in blood over time
AUC represents total drug exposure

Question 4

Bioavailability (absporption)

Answer 4

percent of drug administered that is absorbed into systemic circulation (blood)
%F

Question 5

factors that affect bioavailability (4)

Answer 5

-first pass metabolism in liver
-solubility
-stability in GI tract
-formulation (coating, particle size etc)

Question 6

volume of Distribution (Vd)

Answer 6

amount of fluid required to contain the entire drug in the body at the same concentrations measured in plasma at steady state
-amount of drug that moves from blood to tissues, organs and bones
-does not correspond to specific physiologic volume or spae
-water soluble compounds have small volume of distribution (large hydrophilic)
-lipophilic drugs have large volume of distribution (small)

Question 7

elimination rate constant Kel

Answer 7

value used to describe how quickly drug being eliminated from body

Question 8

half life t1/2

Answer 8

amount of time it takes for plasma drug concentration to be reduced by one half
-assumes constant proportion of drug eliminated over time
-take about 5-6 half lives to clear a drug from body
-help determine how often a drug needs to be given to maintain effective concentration
-inversely proportional to rate of elimination

Question 9

First order kinetics

Answer 9

exponential - rate of elimination diretly proportional to drug concentration (half life is constant and contracnt proportion of drug eliminated per unit of time)
-50% per 2 hours

Question 10

zero order kinectics

Answer 10

linear - constant amount of drug is eliminated per unit time
-50 mg per 2 hours

Question 11

Total body clearance (CL)

Answer 11

volume of body fluid from which the parent drug has been removed, all mechnisms of elimination
mls/hour

Question 12

Bioequivalene

Answer 12

Two drugs pharmaceutically equivalent or alternative, and their bioavailabilites in terms of rate (Cmx and tmax) and extent of absorbtion (AUC), aften administration of same molar dose under same conditions are similar to such a degree that their effects can be expected to be essentially the same

Question 13

determining bioequivalece

Answer 13

release of drug substance from drug product into systemic circulation
-compare concentrations of drug in systemic circulation over time between test and reference product
-Cmax = rate of exposure (peak levels)
-AUC = extent of exposure (total levels)

Question 14

2 way crossover study

Answer 14

each subject recieves test and reference formulations separated by washout period
-less subjects required compared to parallel design

Question 15

replicated crossover design

Answer 15

formulations are admnistered more than one in same subjects
-drugs with known high variable pharmacokinetics
-less subjects required than 2 way crossover
-subjects need to return for more study periods

Question 16

washout period

Answer 16

drug free time interval between study periods, long enough to permit elimination of drug form body
-accounts for various elminiation rates between individuals-8-10 times the mean terminal half-life
-should not exceed 4-5 weeks, may need parallell study if it does

Question 17

parallel study design

Answer 17

drugs with long half-life or some depot formulations
-one period, no washout, no crossover
-larger sample size needed to show bioequivalence