What are the fates of drug distribuition in the body
- Binding and storage in tissues
- Biotransformation (into metabolites)
- Metaboluites in systematic circulation
- Renal excretion
- Biliary excretion
How does protein bind to drugs (method)
Non-covelent binding (also reverible to maintain bound:free)
How can drug interactions be explained due to protein binding and ex
2 drugs may both bind to albmin but one may displace the other off of it increasing the free concentration of the drug causing a increased phamo effect (as + morophine)
-Low albumin can also cause this
What is the isoelectric point and what does it indicate
Ph5= 100 pos and 100 neg charges
What can increased billirubin but low albumin cause
increased conc of free biliirubin causing jaudice
What causes kernicterus
failled billirubin tx where it will actially migrate to brain tissue staining it
How will non polar vs charged molecules move thru body water
charged molecules will only be in extracellular space where non polar will distribute thru total body water
What is the calculation for conc of a drug + apparent volume of distribution
Concentration (drug in plasma)= mass (ammount of drug)/ Volume (of distribution)
Vd= mass of drug given/ conc in plasma
For meaningful interpretation of the apparent volume of distribution you should
Should be evaluated from the conc of the free unbound drug
What is half life
is the time elapsed for its plasma conc to be reduced by 50%
How much longer is the effect of the drug extended when dose it doubled
extended by one half life
how many hal lifes does it take to reach steady state in oral administration
5
What is the wash out period and how long does it take to get back to a drug conc of zero after stopping IV
wash out period- when administration is stopped
-5 half lives to reach zero
When you repetedly administer an oral drug to steady state what will you see
Will see a rise and fall in conc slow and steady up until steady state
How many half lives will it take to reach steady state again if you double dose
5
how to asses oral bioavaility compared to IV (equation)
bioavailality= (AUC oral/AUC IV) * 100
auc=area under curve
What is the formula for desired dose
volume of distribution* desired dose/ bioavailability
Bioavail= 1 in IV
