RE : Con't: fast and slow absorption

From: "Mouksassi Mohamad-Samer" mohamad-samer.mouksassi@umontreal.ca Subject: RE : [NMusers] Con't: fast and slow absorption Date: Wed, 15 Nov 2006 14:56:39 -0500 Dear Jian, Use the CMT to put a dose into each depot compartment : example your total dose is 100 mg put 100 mg into each dose compartment CMT=1 and CMT=2 in data file then in $PK F1=THETA(1) F2=1-THETA(1) Now you have F1 available dose into the first depot ; example 30 % and 70 % in the second depot. This assumes that 100 % of your dose is bioavailable and F1 and F2 trick is to divide the dose between the two absorption components. see fragment control file below $SUBR ADVAN6 $MODEL COMP (FAST) COMP (SLOW) COMP (CENTRAL) $PK F1=THETA(1) F2=1-THETA(1) etc... $DES DFAST=A(1) DSLOW=A(2) DCP=A(3)/V3 DADT(1)= -KA1*DFAST DADT(2)= -KA2*DSLOW DADT(3)= IN - DCP*CL IN= KA1*DFAST + KA2*DSLOW DADT(3)= IN - DCP*CL Hope this helps, If you have a change-point model ie the two processes are sequential rather than parallel Search for the presentation bye Joel Owen at ECPAG about this issue. See also this article to see how to constrain the bioavailibilities should you use an eta on them : Csajka C, Drover D, Verotta D. The use of a sum of inverse Gaussian functions to describe the absorption profile of drugs exhibiting complex absorption. Pharm Res. 2005 Aug;22(8):1227-35 Samer Samer MOUKSASSI PhD candidate universit de montral