Problem: A 50 kg woman was given a single IV dose of an antibacterial drug at a dose level of 6.0 mg/kg. Blood samples were taken at various time intervals. The concentration of the drug (Cp) was determined in the plasma fraction of each blood sample and the following data were obtained. After 1.0 hour after receiving the dose the drug plasma concentration was 7.23 mg/L. After 6.0 hours the drug plasma concentration was 3.09 mg/L (a) Assuming first order elimination kinetics, determine the pharmacokinetic parameters, k, t1/2, and Vd for this drug. k = -ln(3.09)-ln(7.23)/(6-1) = 0.17 t1/2 = ln(2)/0.17 = 4.077 Vd = X0/Cp0 X0 = 6.0mg/kg * 50kg = 300mg ln Cp0 = ln Cp + kt = ln 7.23 + 0.17 x 1 = 2.148 Cp0 = e^2.148 = 8.568 Vd = 300 / 8.568 = 35.014 L (b) How long would it take for 40.0% of the drug to be eliminated? Need Assignment Help?