RE: Two formulation of the same Drug
From: "Gobburu, Jogarao V"
Subject: RE: [NMusers] Two formulation of the same Drug
Date: Tue, 30 Apr 2002 10:24:23 -0400
Dear Gautam,
1. Firstly, as you pointed out, you should probably test for the difference in
the rate of absorption and/or relative bioavailability of X and Y. CL and V are
fundamental properties of the drug and not necessarily of the formuation. So,
please try the following:
TVCL=THETA (1)
CL=TVCL*EXP (ETA (1))
TVV=THETA (2)
V= TVV*EXP (ETA (2))
K= CL/V
TVKA=THETA(3)*DOSE + THETA(4)*(1-DOSE)
KA = TVKA
F1 = 1*DOSE + THETA(5)*(1-DOSE) ; Theta(5) is the bioavailability
of DOSE=0 formulation relative to DOSE=1
2. Further, since you have two occasions of treatments try to test if inclusion
of inter-occasion variability is important on CL and V.
Regards,
Joga Gobburu,
Team Leader, Pharmacometrics,
CDER, FDA.