Re: Request for help about M-M kinetics

From: alison@c255.ucsf.EDU (ABoeckmann) Subject: Re: Request for help about M-M kinetics Date: 17 Sep 1997 14:40:26 -0400 Honghui Zhou sent the following request for help. I haven't run the problem, but I can see an error in the differential equations: DADT(1)=-K12*A(1) DADT(2)=-K12*A(1)-K23*A(2)+K32*A(3)-C2*VM/(KM+C2) DADT(3)=K23*A(2)-K32*A(3) The sign in the second d.e. for K12 is clearly wrong. It should be: DADT(2)= K12*A(1)-K23*A(2)+K32*A(3)-C2*VM/(KM+C2) With no drug entering cmt. 2 from cmt. 1, it is not surprising that the levels are too low. Honghui, please try with the corrected d.e. and see if this helps. You did not include the $INPUT record, but from the looks of the data it must be something like $INPUT ID TIME AMT DV The dosing pattern is very regular. You might find that the run times are faster if you use a single steady state dose event record at TIME 360 with SS=1 and II=12 (on the assumption that, after approx. 30 doses, the subjects have reached steady state). Alison Boeckmann