Does the pharmacokinetic profile shift at natural age breakpoints?
An early step in analyzing children’s toxicokinetic data is deciding whether and how to create bins across ages. The rapid development of children requires that the population be broken into relatively small age groups, particularly in the early postnatal period. If larger bins are used, the data may become highly variable, with age specificity becoming a causality of the desire to simplify the assessment. Thus, bins must be constrained to reflect key developmental stages. Nevertheless, it is useful to make them as large as possible, as this maximizes the number of subjects per group and enhances the power of cross-age comparisons. It should be noted that similar age binning may occur in the exposure and toxicodynamic areas to reflect critical changes in behavior or windows of heightened vulnerability. At some point the children’s kineticist may be asked to adjust his bins to match those created in these other areas for the sake of harmony and to allow risk calculations for neatly defi
