Fig. 2.

Determination of absorption rate constant and portal concentration from human clinical data. A. Observed plasma concentration-time profiles of OXA after a single oral dose of 1000 mg in Sudanese patients (●) and healthy volunteers (○). The human values are from previously published PK data (Daneshmend and Homeida, 1987) with the Y-axis units converted from ng/ml to μM. B. The PK data of the patients (C) were replotted on a semi-logarithmic scale, and the terminal phase was back extrapolated to the Y-axis. Patient plasma concentration values (C) were subtracted from the corresponding concentration from the extrapolated terminal line (C′, yellow line). Plotting the difference (C″) between the extrapolated and the observed concentrations for each time in the absorption phase constructs the residual line (green line). The absorption rate constant was determined from the slope of the residual line. The calculated total hepatic inlet concentrations of OXA in patients and healthy volunteers were 94 μM and 78 μM, respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)