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Unformatted text preview: PHARMACEUTICS 405 Winter 2007  ' Name
Midterm #1 Student # January 19, 2007 Questions Points . 1 28
2 26
3. 18
4. . 14
5 10
6 4 TOTAL 100 Student #
(28 pts) Check the appropriate answer  The first order elimination rate constant, K, represents the fraction of the amount
of drug in .the body that is eliminated per unit time True False In the following relationship C = C0 eKt , the term CO is equal to the amount
of drug in the body at time zero True False .In the following relationship C = C° e'Kt ' to the intravenous dose administered , the term CO is directly proportional True False In the relationship C = Ae'OlJE + Be‘l3t , the term A is equal to the plasma
concentration at time zero True False A drug that is extensively bound to plasma proteins (fu <0. 1) cannot have a large
volume of distribution (V >100L) True False Drugs that obey two—compartment kinetics have larger volumes of distribution
than drugs that obey one—compartment kinetics True False For a drug that binds to albumin, the fraction unbound in plasma will decrease
when albumin concentration decreases True False  (26 pts) In the table of pharmacokinetic parameters, we can observe that the following drugs exhibit a low extent of plasma protein binding and relatively
large volumes of distribution (> IOOL): Drug Plasma Fraction Volume of Distribution (L)
Unbound ' Ranitidine 0.85 130 Procainamide 0.84 13 0 Metoprolol 0.87 . 290 (i) For each of these drugs, calculate the fraction unbound in tissues. Assume
Plasma Volume = 3L and Total Body Water: 42 L (ii) For metoprolol, calculate the dose required to achieve an initial plasma
concentration of 25 ng/mL ' (18 pts) A 300 mg intravenous dose of ciproﬂoxacin yielded a plasma
concentration of 1.5 mg/L one hour after injection. Given that this drug has a
volume of distribution of 154 L, calculate: (i) its elimination half—life (ii) the elimination rate at 2 hrs (iii) the time required for plasma concentration to decrease to 0.37 mg/L 4. (14 pts) A bi—exponential intravenous curve is given in the attached graph. You
are asked to: a) Calculate the elimination half—life in the beta phase b) Draw on the same graph paper the curve you would expect if the
intravenous dose is doubled 5. (10 pts) Procainamide is a drug indicated for the treatment of atrial arrythmias.
On intravenous dosing, procainamide demonstrates pronounced 2compartment
pharmacokinetics and distributes into adipose tissue. Clinical studies have ,
documented that both the desired effect and toxicity of procainarnide is associated
with the central compartment. RE is a 75 kg, 6 ft tall male who has been admitted
to the CCU for treatment of his atrial arrhythmia. Calculate an intravenous
loading dose regimen for procainamide hydrochloride given the following information.
V1 = 0.7 L/kg 'Vﬁ = 2.0 L/kg S = 0.87 procainamide HCL
Tl/Za: 5 min Tums: 3 hr Therapeutic range: 48 mg/L
F = bioavailability = 1.0 for IV
. L D = V * C 
F * S 0. ,. CITADEL® No. 554." SEMILOG s )Qz‘o 3 Li‘ _
~F‘IU::‘ / LA;I‘d£’\ (4 pts) BT briskly walked from the parking to the clinic for his 10 am appointment. He has been receiving digoxin 0.125 mg/day for 30 days prior to his appointment. He took his morning dose at 7 am. If a blood sample is drawn
immediately on arriving to the clinic, his digoxin serum concentrations will be ' difﬁcult to interpret when compared to the recommended therapeutic range for digoxin. Explain the reason(s)? _ D
ﬁ'AUCo/s
AUC=£+§ a {3
1 0.693
_ﬁ=___._
2 l3
f —@ — 1
u_Ct ‘1+Ka[P] V=V+VLL
P_TfT EQUATIONS Albumin Concentration in plasma = 5 x 10'4m01/L 6 CITADEL® NO. 653 — SEMI~LOG 3 X 10 ...
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 Spring '08
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