Dear all, I try to model simultaneously a parent drug and its metabolite using a 2 compartments dynamic enzymatic model (using the general enzymatic reaction E+S-->(ES)-->E+P). Here is the control stream :
$PROB TEST MODELISATION NLIN 2CPMT $INPUT ID TIME DV AMT MDV CMT $DATA DATA131.csv IGNORE=# $SUBROUTINE ADVAN8 TOL4 ; Modèle Non linéaire 2 cpts $MODEL COMP= (CENTRAL,DEFDOSE) ; cpt 5FU COMP= (CENTRAL,NODOSE) ; cpt 5FDHU COMP= (CENTRAL,NODOSE) ; enzyme **(1)** $PK V1 =THETA(1)*EXP(ETA(1)) ; Vd 5FU V2 =THETA(2)*EXP(ETA(2)) ; Vd 5FDHU CL10 =THETA(3)*EXP(ETA(3)) ; Cl d'élimination 5FU CL20 =THETA(4)*EXP(ETA(4)) ; Cl d'élimination 5FDHU KE1 =THETA(5)*EXP(ETA(5)) ; Cstte de métabolisation KE2 =THETA(6)*EXP(ETA(6)) ; Cstte de métabolisation ET =THETA(7)*EXP(ETA(7)) ; total enzyme K10=CL10/V1 K20=CL20/V2 S1=V1 S2=V2 $DES B= ET-A(3) DADT(1)= -K10 *A(1)-KE1*B*A(1) DADT(2)= KE2 * A(3) - K20 * A(2) DADT(3)= KE1 * B*A(1)-KE2*A(3) $ERROR IPRED=F IF (CMT.EQ.1) THEN Y=F*(1+EPS(1))+ EPS(2) ELSE Y=F*(1+EPS(3)) ENDIF IRES=DV-IPRED $THETA (0,10,20) (0,60,100) (0,1,10) (0,1,10) (0,1,10) (0,1,10) (0,1,10) $OMEGA (1) (1) (1) (1) (1) (1) (1) $SIGMA (0.01) (0.01) (0.01) $EST METHOD=1 SIG=3 MAXEVAL=9999 **(1)** : this compartment was added because of the enzyme own equation (DADT(3)). With FO, I'm trying to estimate the parameters But with FOCE, the run stop immediately! ERROR IN NCONTR WITH INDIVIDUAL 1 ID=0.10000000E+01 NUMERICAL HESSIAN OF OBJ. FUNC. FOR COMPUTING CONDITIONAL ESTIMATE IS NON POSITIVE DEFINITE 1)Are there any problems in the control stream? 2)The model is overparametrized? Should I have to fixed parameters? (I have over one hundred couple of kinetics with 5-7 observations for each) I would really appreciate aany advice, thanks. Christian