NONMEM codes about PK analysis from a cross-over study design
Dear NONMEM users,
I have a data set from a bioavailablity study (2×2 study design). 18
people took a single dose of a marketed drug (marked as R), then after a
wash-out period, took a single dose the corresponding generic drug (marked T).
I want to estimate the PK parameters of T and R seperately. One approach we
handle the dataset is to consider the 18 people as 36 people. Is it right?
I still want to handle them as 18 people. I read something useful in the NONMEM
guides on EVID, but still comfused about the data file structure and the NONMEM
codes.
Thank you very much ahead for any comments.
Xipei Wang
Beijing, China
Part of my codes and data are as below:
data set:
ID TIME AMT DV EVID DRUG
1 0 100 . 1 1
1 0.3 . 0.7 0 1
1 0.5 . 2 0 1
....
1 48 . 0.6 0 1
1 0 . . 3 .
1 0 100 . 1 2
1 0.3 . 0.3 0 2
1 0.5 . 1.6 0 2
....
NONMEM CODES：
$INPUT ID TIME AMT DV EVID DRUG
$DATA sample.csv
$SUBROUTINES ADVAN2 TRANS2
$PK
KA=THETA(1)*EXP(ETA(1))
CL=THETA(2)*EXP(ETA(2))
V=THETA(3)*EXP(ETA(3))
IF (DRUG.EQ.2) THEN
KA=THETA(4)*EXP(ETA(4))
CL=THETA(5)*EXP(ETA(5))
V=THETA(6)*EXP(ETA(6))
ENDIF
S2=V/1000
$ERROR
Y=F+ERR(1)
$THETA
(0, 2) ;KA
(0, 8) ;CL
(0, 4) ;V
(0, 2) ;
(0, 8) ;
(0, 4) ;
$OMEGA
0.04
0.04
0.04
0.04
0.04
0.04
$SIGMA
0.04
$ESTIMATION MAXEVAL=9999 METHOD=1