Intra- and inter-subject variabilities of CGP 33101 after replicate single oral doses of two 200-mg tablets and 400-mg suspension

Abstract

Purpose: The purpose of this study was to use a replicate designed trial to assess the overall, intra- and inter-subject variabilities in pharmacokinetic parameters of CGP 33101 after oral administration of tablets relative to that of powder suspended in water, and to determine the relative proportion of the intra-subject variance to the overall variability.

Methods: Sixteen healthy subjects were randomly assigned to four groups to receive tablets and suspension twice in four different treatment sequences. The plasma concentration-time profile of CGP 33101 was characterized in terms of Cmax, Tmax, and AUC. Bioavailability of tablets relative to suspension and intra- and inter-subject variability were assessed by statistical analysis.

Results and conclusions: The overall variabilities in absorption kinetics of CGP 33101 in healthy subjects were small with CV's of the population mean values for AUC and Cmax less than 26% for both tablets and suspension. Contribution of intra-subject variability to the overall variability was also small (approximately 20%). Both the overall and intra-subject variabilities of AUC and Cmax after suspension were larger than after the tablets. However, the differences in variability between tablets and suspension were not statistically significant (p > 0.05). The tablet formulation was bioequivalent to suspension in terms of rate and extent of absorption based on 90% conventional confidence intervals (for AUC and Cmax) and Wilcoxon rank-sum test (for Tmax).