In spite of the recent advances in technology to optimize the absorption, distribution, metabolism and elimination (ADME) properties of new and promising medicinal products to reduce clinical failures, the investigation of drug disposition in the pediatric and elderly populations continues to be under evaluated. With the increasing prevalence of aging populations world-wide, there is a growing concern from health care providers, regulators and the general public that drug delivery is still less than optimal for the vulnerable patient populations likely to be more sensitive to adverse effects of the new investigational drugs. This review of the ClinicalTrials.gov database revealed a rapidly increasing number of clinical trials and a trend towards wider inclusion criteria of the elderly population in clinical trials over the past 10 years. However, when we summarized trials by drug delivery, biological platforms, and disease categories, less than 10% of these trials included pharmacokinetic evaluation in elderly subjects greater than 65 years of age, and less than 4% included pharmacokinetic evaluation in children less than 17 years of age. Across the various disease areas, the percentage of trials that included pharmacokinetic evaluation in the children and elderly has remained low and is consistently less than the studies that included the younger 18 to 65 age group. Therefore, it is not known whether the right information is being generated from the growing number of clinical trials to guide optimal dosing recommendations in special patient populations.