Evaluation of reference-scaled average bioequivalence of two oral formulations of abiraterone acetate in healthy Chinese subjects
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OBJECTIVE: This study was designed to evaluate the pharmacokinetic (PK) properties and bioequivalence (BE) of two 250-mg tablet formulations of abiraterone acetate: a newly developed generic formulation (test) and a branded formulation (reference) in healthy adult Chinese subjects under fasted (n = 40) and fed (n = 40) conditions. MATERIALS AND METHODS: The comparison was performed using a single-dose, open, randomized, and four-way replicate study. The concentration of abiraterone in blood samples taken over 48 hours was determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). To assess the BE of the test and reference formulations, confidence intervals (CI, 90%) for the peak plasma concentration (Cmax) and area under the concentration-time curves (AUC0-t and AUC0-∞) were calculated using the reference-scaled average bioequivalence (RSABE) method. RESULTS: The results showed that the 90% CIs for the ratios of Cmax, AUC0-t, and AUC0-∞ in the fasted study were 90.14 - 114.11, 93.96 - 115.07, and 93.72 - 113.331, respectively. For the fed study, the 90% CIs were 81.83 - 102.51, 91.51 - 104.89, and 91.46 - 104.58, respectively. CONCLUSION: In conclusion, the tested 250-mg abiraterone tablets were bioequivalent to 250-mg Zytiga tablets (reference) under both fasted and fed conditions. In addition, food intake increased the systemic exposure and Cmax of abiraterone by 3-fold and 7-fold, respectively.
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Bioequivalence and Pharmacokinetic Profiles of Agomelatine 25-mg Tablets in Healthy Chinese Subjects: A Four-Way Replicate Crossover Study Demonstrating High Intra- and Inter-Individual Variations.

The present study was designed to assess the bioequivalence of two agomelatine formulations (25-mg tablets) in healthy Chinese male subjects. This single-dose, open-label, randomized, four-way replicate study with a 1-week washout period was conducted in 60 healthy Chinese male volunteers under fasting conditions. Blood samples were collected over a 12-h period after a single dose of the 25-mg agomelatine test (T) formulation or a reference (R) formulation, and the drug concentrations were assayed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Pharmacokinetic parameters were calculated using a non-compartmental model. Bioequivalence between the formulations was assessed. Tolerability and safety were monitored by physical examination, electrocardiogram (12-lead ECG), clinical laboratory tests, and adverse events (AEs). A total of 56 out of 60 subjects completed the study. No AEs were observed. The values of maximum plasma concentration (Cmax), maximum concentration (Tmax), area under curve (AUC)0-t and t1/2 were 12.032 ng/mL, 0.658 h, 12.637 ng·h/mL, and 0.813 h, respectively, for the test formulation, and 10.891 ng/mL, 0.709 h, 11.572 ng·h/mL, and 0.96 h, respectively, for the reference formulation. The intra-individual variability of Cmax and AUC0-t were 78.3 and 61.8%, respectively. The inter-individual coefficients of variance (CVs) of Cmax and AUC0-t were approximately 100%. The 90% confidence intervals for the ratio of means for the log-transformed Cmax (97.7-124.9%), AUC0-t (98.2-118%), and AUC0-∞ (97.8-117.2%) were within the guideline range of bioequivalence (80-125%). The test and reference formulations of agomelatine met the regulatory criteria for bioequivalence of the Chinese Food and Drug Administration. Significant intra-individual and inter-individual variations were found.