11.1 - Dose-Finding (Phase I) Studies

One of the principal objectives of dose-finding (DF) studies is to assess the distribution and elimination of drug in the human system. What level of the drug is appropriate?

Pharmacokinetic (PK) models, also known as compartmental models, provide useful analytical approaches for DF studies. The objective of a PK model is to account for the absorption, distribution, metabolism, and excretion of a drug in the human system. An example of a two-compartment PK model is as follows and the objective is to estimate the rates into, between, and out of the two compartments.

AbsorptionDistributionMetabolismExcretionGastrointestinalSystemCirculatorySystem

Estimates are made for each of these areas, i.e., absorption rate, distribution rate, etc. for the drug in question.