Fx

From: Paul Hutson prhutson@pharmacy.wisc.edu Subject:[NMusers] Fx Date: 5/24/2004 7:22 PM I am modeling an oral drug with both parent and metabolite plasma concentrations available. When using ADVAN6 with differential equations for such extravascular dosing, I understand F2 to represent the bioavailability of the drug in the depot compartment (#1) moving to the central (sampled) compartment (#2). However, it is not clear to me from the manual whether I need to explicitly include F2 in $PK or whether it is inferred.. eg. TVCL=THETA(1) TVV=THETA(2) F2=THETA(3) V2=TVV/F2 S2=V2/1000 VS TVCL=THETA(1) TVV=THETA(2) F2=THETA(3) V2=TVV S2=V2/1000 Also, should the parameter V2 or S2 be used in the differential (or, adjusting for the 10^3 difference, does it matter?)... S2=V2/1000 ; Scaling for parent $DES DADT(1)=-A(1)*KA DADT(2)=A(1)*KA-(A(2)*(CL+CLM))/V2 (S2?) ; eq for parent DADT(3)=(A(2)*CLM-A(3)*CLME)/V2 (S2?) ; eq for METABOLITE Thanks. Paul (P.S. Nice paper on morphine PK in kids in BJA, Nick.) Paul Hutson, Pharm.D. Associate Professor (CHS) UW School of Pharmacy 777 Highland Avenue Madison, WI 53705-2222 Tel: (608) 263-2496 FAX: (608) 265-5421 Pager: (608) 265-7000, #7856