The Simulation of the Relevance of Absorption Rate Constant and Elimination Rate Constant to the Plasma Drug Concentration

To investigate how the concentration characteristics vary with the changing parameters absorption rate constant (K_a) and elimination rate constant (K₁₀) this study simulates a two-compartment model with first-order absorption for oral administration. Based on the MATLAB software the simulations illustrated the results of the variation of the concentration characteristics in two- and three-dimensional diagrams. It was showed that the peak plasma concentration (C_max) increased and the time required to reach this peak (T_max) decreased with the increasing K_a. However, with increasing K₁₀ both the C_max and the T_max decreased. Results demonstrate that the profiles are meaningful for the selection of the rational range of K_a and K₁₀, and the identification of the flip-flop kinetic.