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problems
Hi,
Six hours after 500 mg of a drug is administered by IV injection, a patient's plasma concentration Is 10 microg/ ml .
If T 1/2 = 4 h
( MEC ) = 2 micorg/ ml
How many hours after the first dose should a second dose be administered ?
Here,plasma con is 10micro/ml
1/2 life 4hrs
so 10 mcg/l----------after one half-------5mcg/ml--------time-4hrs
after secoond half----2.5mcg/ml-------another 4hr
then we cann't go for another half because the Mec conc is 2mcg/ml
So the next dose will be after 8hrs.
The radioactive decay of radium has a rate constant of 0.000422 per year. How many years will it take for 20% of the radium initially present to degrade? (The amount initially present can be specified as 100%.)
A. 230
B. 529
C. 1000
D. 3815
The answer is B (529).
T=2.303/k*loga/a-x
Here a-x wiil be =100-20=80%
T=2.303/0.00422*log100/80
T=528.8years
I will try another questions too.I looked these question answers in Mannonsheroff question book....but in that they answerd the questions very vaguly.
regards
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