OBJECTIVE:To evaluate relative
bioavailability and pharmacokintic parameters of digoxin by one step method.METHODS:To predict
the relative
bioavailability and pharmacokinetic parameters of digoxin with NONMEM program and its submodule,POSTHOC.RESULTS:There was no statistical significent difference between NONMEM program and 3P87 approach on evaluating relative bioavailability and
pharmacokinetics of digoxin in eight Chinese healthy male volunteers.The typical value of mainly population pharmacokinetics, K 10 (h -1 ), V c/ F(L) and β(h -1 ),of digoxin in young healthy volunteers were 0.115 ,128 and 0.018 respectively.The typical value of K 10 (h -1 ), V c/ F(L) and β(h -1 ),of digoxin in aged patients were 0.040 3 , 76.0 and 0.014 8 respectively.CONCLUSIONS:The elimination rate of digoxin in aged patients was significantly lower than the in young healty volunteers.The individual pharmacokinetic parameters of aged patients fitted by NONMEM using POSTHOC module for aparse data( n =3～4) were similar to it obtained by PKBP N1 program for normal data( n =5～7).