[NMusers] Help with a PK code

From: Niurys.CS <amaranthfan_at_gmail.com>
Date: Tue, 23 Apr 2019 07:34:17 -0500

Dear All,

I'm working on the population pharmacokinetics of a mAb, in this study
 4 dose levels (50, 100, 200 and 400 mg) were evaluated. I tested
different models, but none of them fit well; that's why I decided to
find for each dose level the best model. I found the two lower dose
levels fitted to Michaelis Menten + CL linear model and the two higher
dose levels fitted to QSS Rtot model.
I think if I use this code, I'll find the best model for my data, so I
appreaciate your suggestions:

$PK

TVCL= THETA(1)
TVV1= THETA(2)
TVQ = THETA(3)
TVV2 = THETA (4)

TVKM = 0
TVVM = 0

IF(DOS.LT.200) THEN
TVKM = THETA (5)
TVVM = THETA (6)

TVKSS = 0
TVKINT = 0
TVKDEG = 0
TVRMAX = 0

IF(DOS.GT.100) THEN

TVKSS = THETA (7)
TVKKINT = THETA(8)
TVRMAX = THETA(9)

ENDIF


K = CL/V1
K12 = Q/V1
K21 = Q/V2
S1 = V1

;----------------------------------
$DES

CONC=0.5*(A(1)/V1-RMAX-KSS)+0.5*SQRT((A(1)/V1-RMAX-KSS)**2+4*KSS*A(1)/V1)

DADT(1) = -(K+K12)*CONC*V1+K21*A(2)-KINT*RMAX*CONC*V1/(KSS+CONC)-VM*CONC*=
V1/(KM+CONC)
DADT(2) = K12*CONC*V1-K21*A(2)


Thank you,

Regards,
Niurys de Castro

--

MSc Niurys de Castro Suárez
Profesor Asistente FarmacometrĂ­a
Investigador Agregado
Departamento Farmacia
Instituto de Farmacia y Alimentos, Universidad de La Habana
Cuba

Received on Tue Apr 23 2019 - 08:34:17 EDT

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