Weibull distribution
Dear NONMEM users,
I have tried to study the pk profiles of a drug after multiple oral dosage regimen of 500mg every 12hr. The estimation process was well performed with the first dose (only) using Weibull function. but if i apply the same control file to the whole data (ie, single dose and multiple doses), it does not work any more. I can not detect my error. Could any one tell me where is it? neither first order nor Mich.-Menten models fitted the data like weibull model.
thank you very much in advance for your response.
sincerely yours
Abduljalil
$SUBROUTINES ADVAN6 TRANS1 TOL=3
$MODEL
COMP=(DEPOT,DEFDOSE)
COMP=(CENTRAL,DEFOBS)
$PK
CL=THETA(1)*EXP(ETA(1))
V=THETA(2)*EXP(ETA(2))
BETA=THETA(3)*EXP(ETA(3))
ALPHA=THETA(4)*EXP(ETA(4))
K=CL/V
S1=1
S2=V
$ERROR
DEL=0
IF(F.EQ.0) DEL=0.001
W=F
IPRED=F
IRES=DV-IPRED
IWRES=IRES/(W+DEL)
Y=F+EPS(1)
$DES
DADT(1)=-A(1)*(BETA/ALPHA)*((TIME/ALPHA)**(BETA-1))*EXP(-(TIME/ALPHA)**BETA)
DADT(2)=-DADT(1)-A(2)*K
$THETA
(0.01,17,80);
(10,115,900);
(0.1,2.2,30)
(0.1,2.6,30)
(0.001,2)
(0.001,1)
$OMEGA
0.1 0.2 0.08 0.2
$SIGMA
0.2
$EST METHOD=1 INTER PRINT=5 NOABORT MAXEVAL=9999