Chapter 8 - Problem 4

Linear Plot of Cp versus Time after IV or Oral Administration

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A drug was administered as an IV injection, and oral solution and two tablet formulations (one rapid and the other a slow release tablet). A dissolution step was included to model the two tablet formulations. Parameters values included kel = 0.077 hr^-1,V = 81.3 L, ka = 0.113 hr^-1. The two tablet formulations required kd = 0.405 hr^-1 or 0.0261 hr^-1. The dose were 25000 mg (Dose1 IV bolus), 20300 mg (Dose2 Oral solution), 19000 mg (Dose3 Oral rapid release tablet) and 21600 mg (Dose3 Oral slow release tablet). Simulate the concentration versus time curves after each dose. Bevill et al., 1977. Add additional lines using the Add Line button.

Figure 8.4.1 One Compartment Model with Dissolution and Absorption

The equations for this model after IV Bolus, Solution, and Tablet doses were developed using Laplace transforms.

	IV Bolus	Oral Solution	Oral Tablet (fast)	Oral Tablet (slow)
Dose1	25000
Dose2		20300
Dose13			19000	21600
kel (hr^-1)	0.077	0.077	0.077	0.077
V (L)	81.3	81.3	81.3	81.3
ka (hr^-1)		0.113	0.113	0.113
kd (hr^-1)			0.405	0.0261

References

Bevill, R.F., Dittert, L.W. and Bourne, D.W.A. 1977 Disposition of Sulfonamides in Food-Producing Animals IV: Pharmacokinetics of Sulfamethazine in Cattle following Administration of an Intravenous Dose and Three Oral Dosage Forms, J. Pharm. Sci., 66, 619-23