POPULATION ANALYSIS IS THE METHODOLOGY USED TO QUANTIFY INTERSUBJECT VARIABILITY IN KINETIC STUDIES. IN THIS RESEARCH PROJECT, WE PROPOSE TO DEVELOP A GENERAL POPULATION ANALYSIS PACKAGE, AND TO INTERFACE THIS PACKAGE WITH THE CURRENT SAAM II MODELING PROGRAM. THIS PACKAGE COULD TYPICALLY BE USED FOR THE POPULATION MODELING OF PHARMACO-KINETIC/PHARMACODYNAMIC SYSTEMS AND TRACER KINETIC SYSTEMS. POPULATION ANALYSIS IS WIDELY USED IN PHARMACOKINETIC STUDIES SINCE IT IS THE KEY TO UNDERSTANDING HOW DRUGS BEHAVE IN HUMANS AND ANIMALS. IT PROVIDES THE FOUNDATION FOR THE INTELLIGENT DESIGN OF DOSAGE REGIMENS TO TREAT DISEASE PROCESSES. IN METABOLIC STUDIES, IT IS USED TO IDENTIFY WHICH PARAMETERS IN A MODEL CHANGE WHEN A POPULATION OF NORMAL SUBJECTS IS COMPARED TO A POPULATION OF SUBJECTS WITH A KNOWN PATHOLOGICAL CONDITION. RFKA IS SUPPORTING THE INITIAL DEVELOPMENT OF A PROTOTYPE FOR THE PARAMETRIC METHOD; THIS IS CURRENTLY BEING TESTED USING SIMPLE BUT STANDARD PHARMACOKINETIC MODELS. AN R-01 HAS BEEN SUBMITTED TO SUPPORT THE FULL DEVELOPMENT AND IMPLEMENTATION OF A POPULATION ANALYSIS MODULE.