modeling compartments within compartments

From: rjames@rhoworld.com Subject:[NMusers] modeling compartments within compartments Date: 10/13/2003 10:17 AM Dear all, I am trying to fit a model where a compund is cleared in both a protein-bound and free-state from the central compartment by different processes at different rates. The drug assay concentration data does not distinguish between the protein-bound and free drug states and thus measures only total drug concentration. So, the protein-bound state is like another compartment with its own clearance rate but with the drug concentration observations being the combined total drug in both compartments. Can I model the drug observations as the combined total drug from two compartments? Robert James .. Robert L. James, M.S., M.Stat. Senior Biostatistician Rho, Inc. 100 Eastowne Drive Chapel Hill, NC 27514 (919) 408-8000 x 468 (919) 408-0999 (fax) rjames@rhoworld.com