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

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 C-max, T-max, 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 C-max less than 26% for both tablets and suspension. Contribution of intra-subject variability to the overall variability was also small (similar to 20%). Both the overall and intra-subject variabilities of AUC and C-max 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 C-max) and Wilcoxon rank-sum test (for T-max).