Dear Amy,
4 different doses were given orally, therefore F1 is fixed to 1.
Below you find the code, hope this helps you,
Thanks again,
Silke
$PK
;--------------Absorption parameters-------------------
F1 = THETA(1)
KA = THETA(2)
;--------------Disposition parameters-------------------
V2 = THETA(3)
Q3 = THETA(4)
V3 = THETA(5)
CL = THETA(6)
;--------------Binding parameters-----------------------
BMAX = THETA(7) ; concentration of binding parameters in central cmt
KD = THETA(8) ; affinity constant
AMAX2 = THETA(9) ; amount of binding parameters in peripheral cmt
S2=V2
AMAX=BMAX*S2
K1=KD*V2
K2=KD*V3
K20=CL/V2
K23=Q3/V2
K32=Q3/V3
$DES
; Protein binding in central compartment
;----------------------------------------------------------
LIN1 = -K20*A(2)+K32*A(3)-K23*A(2)+KA*A(1)
BIND1 = AMAX*K1/(A(2)+K1)**2
; Protein binding in peripheral compartment
;----------------------------------------------------------
LIN2 = K23*A(2)-K32*A(3)
BIND2 = AMAX2*K2/(A(3)+K2)**2
DADT(1)= -KA*A(1)
DADT(2)=LIN1/(1+BIND1)
DADT(3)=LIN2/(1+BIND2)