Cefixime absorption kinetics after oral administration to humans.

Cefixime (CFX) absorption kinetics after oral administration to humans was studied. Four distinct models, incorporating a delay of absorption and first-order elimination kinetics, i.e. first-order absorption (M1), zero-order absorption (M0), Michaelis-Menten type absorption (MM) and Michaelis-Menten type absorption with 'an absorption window' (MM-delta t) were used to fit concentration data of CFX in 10 Chinese men following an oral dose of 400 mg. r2 and AIC were selected as measures of goodness-of-fit. The results show that the MM-delta t model provided a better fit than the other three models. The kinetic parameters were estimated as follows: Vmax' = 10.80 +/- 3.80 mg.l-1.h-1; K(m)' = 88.31 +/- 2.75 micrograms.ml-1; delta t = 4.75 +/- 0.85 h; T1/2 = 4.20 +/- 0.92 h; Tmax = 5.20 +/- 0.92 h; and Cmax = 6.04 +/- 1.70 mg.l-1.