(no subject)

Hi I am trying to build a structural model for an oral drug. I am getting extremely large and unreasonable values for vd, eg a billion L, putting an upper limit on theta will give a near boundary warning. Does anyone have an idea why this might occur and how to solve it. This is part of the input file: $SUBROUTINE ADVAN2 TRANS2 $PK TVCL = THETA(1) CL = TVCL*EXP(ETA(1)) V = THETA(2) KA = THETA(3) S2 = V $THETA (0,10) $THETA (0,20) $THETA 2 FIXED Best regards Susan