PRED capped

dear community, I use a previously validated model of capecitabine in a new data-set. While the model converges successfully, PRED for all metabolites/compartments are 'capped' for PRED (at 1.6 for compartment 2, 2.4 for compartment 3, 3.0 for compartment 4 and 1.2 for compartment 5). At the same time, IPRED's are not 'capped', and GoF look nice. In a previous data-set using the same model, this phenomenon did not occur. Any suggestion is very wellcome, best regards Markus Control stream (capecitabine = compartment 2, DFCR = compartment 3, DFUR = compartment 4, 5FU = compartment 5): $PROB RUN# 001 $INPUT C ID TIME AMT DV CMT MDV EVID STUDY NR SEX AGE LIVERM WT BSA PS BILI Krea ASAT ALAT T85C A496G G1601A A1627G T1896C EXON14S A2846T C24T G1249A A4145G C4488T GSTT1 GSTP1 GSTM1 TSTR TS3CG TYMSPHENO TS3UTR MTHFR ERCC1 XRCC1 GSTP1B GASTRECT $DATA cap5.CSV IGNORE=C $SUBROUTINES ADVAN6 TOL=6 $MODEL NCOMPARTMENTS=5 COMP=(DOS) COMP=(CAP) COMP=(DFCR) COMP=(DFUR) COMP=(5FU) $PK TVKA=THETA(1) KA=TVKA*EXP(ETA(1)) ;absorption rate constant.1 TVV2=THETA(2) V2=TVV2*EXP(ETA(2)) ;CAP distribution volume.2 TVV3=THETA(3) V3=TVV3*EXP(ETA(3)) ;DFCR distribution volume.3 TVV4=THETA(4) V4=TVV4*EXP(ETA(4)) ;DFUR distribution volume.4 TVV5=THETA(5) V5=TVV5*EXP(ETA(5)) ;5FU distribution volume.5 TVQ1=THETA(6) Q1=TVQ1*EXP(ETA(6)) ;CAP > DFCR.6 TVQ2=THETA(7) Q2=TVQ2*EXP(ETA(7)) ;DFCR > DFUR.7 TVQ3=THETA(8) Q3=TVQ3*EXP(ETA(8)) ;DFUR > 5FU.8 TVCL1=THETA(9) CL1=TVCL1*EXP(ETA(9)) ;CL1-CAP.9 TVCL2=THETA(10) CL2=TVCL2*EXP(ETA(10)) ;CL2-5FU.10 ALAG1=THETA(11)*EXP(ETA(11)) ;ALAG1.11 F1=0.95 S2=V2/1000 S3=V3/1000 S4=V4/1000 S5=V5/1000 K23=Q1/V2 K34=Q2/V3 K45=Q3/V4 K20=CL1/V2 K50=CL2/V5 $ERROR CALLFL=0 IPRE=-3 FLG2=0 FLG3=0 FLG4=0 FLG5=0 IF(CMT.EQ.2)FLG2=1 IF(CMT.EQ.3)FLG3=1 IF(CMT.EQ.4)FLG4=1 IF(CMT.EQ.5)FLG5=1 IF(F.GT.0) IPRE=LOG(F) Y=LOG(F)+EPS(1)*FLG2+EPS(2)*FLG3+EPS(3)*FLG4+EPS(4)*FLG5 W=1 IRES=DV-IPRE IWRES=IRES/W $DES DADT(1) = -KA*A(1) DADT(2) = KA*A(1)-K23*A(2)-K20*A(2) DADT(3) = K23*A(2)-K34*A(3) DADT(4) = K34*A(3)-K45*A(4) DADT(5) = K45*A(4)-K50*A(5) $THETA (0,16) ;KA.1 (0,580) ;V-CAP.2 1 FIX ;V-DFCR.3 1 FIX ;V-DFUR.4 1 FIX ;V-5FU.5 (0,24) ;CAP > DFCR.6 (0,16) ;DFCR > DFUR.7 (0,8) ;DFUR > 5FU.8 (0,180) ;CL1-CAP.9 (0,75) ;CL2-5FU.10 (0,0.2) ;ALAG1.11 $OMEGA 0.14 ;KA.1 0 FIX ;V-CAP.2 0 FIX ;V-DFCR.3 0 FIX ;V-DFUR.4 0.14 ;V-5FU.5 0.14 ;CAP > DFCR.6 0.14 ;DFCR > DFUR.7 0.14 ;DFUR > 5FU.8 0.14 ;CL1-CAP.9 0.14 ;CL2-5FU.10 0 FIX ;ALAG1.11 $SIGMA 0.14 ;CMP2 0.14 ;CMP3 0.14 ;CMP4 0.14 ;CMP5 $ESTIMATION PRINT=5 MAXEVAL=5000 METHOD=1 INTER NOABORT POSTHOC SIGDIG=3 MSFO=MSF020B $COVARIANCE MATRIX=R $TABLE ID TIME AMT CMT IPRE IWRES CL1 CL2 V2 V3 V4 V5 NOPRINT ONEHEADER FILE=cap8.TAB -- Markus Joerger MD-PhD ClinPharm Medical Oncology&Clinical Pharmacology Department of Internal Medicine Kantonsspital St. Gallen Switzerland [email protected] Phone: +41-765591070 Fax: +41-714946325