Homework Assignment 1995 - 3 (Answers)

Problem 3

Converting t1/2 = 7 hr to kel gives a value of 0.099 hr-1

1) Since Cp(ss) = k0/(kel*V); k0 can be calculated as Cp(ss) * kel * V = 25 x 0.099 x 25 = 61.9 mg/hr

2) To achieve Cp(0) = 25 mg/L with a bolus dose give Cp(0) * V = 25 x 25 = 625 mg

3) To reach Cp(0.5) = 25 mg/L with a fast infusion rearrange: Cp(T) = (k0/(kel*V)) * (1 - e-kel*T) to give k0(fast) = Cp(T)*kel*V/(1-e-kel*T) = 25 x 0.099 x 25/(1 - e-0.099 x 0.5) = 1280 mg/hr for 30 minutes (ONLY!!!)

Sketch as a linear graph

1) Slow infusion - blue squares

2) I.V. Bolus - green circles

3) Fast infusion - red triangles

Summary in Tabular Format
Parameter Value Units
k0(slow) 61.9 mg/hr
Dose (bolus) 625 mg
k0(fast) 1280 mg/hr