Question

Is this statement true? The only difference between the compartmental and noncompartmental methods of analysis is in how the nonaccessible portion of the system is described.

Answer 1

Yes it is true that the only difference between compartmentalize and non compartmentalize methods is the difference in the analysis of nonaccessable portion of the system descriptions. Non-compartmental method used to calculate pharmacokinetic parameters does not assume the number of compartments. It assumes that elimination follows first order. This method is simple and used commonly to calculate pharmacokinetic parameters such as half-life, clearance, and volume of distribution. Compartmental models do not assume instantaneous distribution of drug throughout the body and you may find two or more segments in the elimination phase when you plot log concentration versus time on a graph paper. Whereas in non-compartmental model you will find a straight line in the elimination phase, this is because the drug is assumed to be instantaneously distributed througout the body and the drug is mostly confined to blood volume. These compartments can be explained using macro or micro rate constants.