Bioequivalence of a Generic Quetiapine (Ketipinor®) in Healthy Male Volunteers

Abstract

Quetiapine is an atypical antipsychotic indicated for the treatment of schizophrenia and related psychoses. Uses of generic drugs are essential due to economic reason. Interchangeability of drugs is determined by bioequivalence studies. We aim to study the bioequivalence of a generic quetiapine (Ketipinor ® , Orion Corporation, Finland) and the innovator product (Seroquel ® , AstraZeneca, UK). The study was a randomized, two-way crossover design with a two-week washout period in 24 healthy Thai male volunteers. After a single 200-mg oral dosing, serial blood samples were collected at appropriate interval up to 48 h. Plasma quetiapine concentrations were determined by using a validated LC-MS/MS method. Pharmacokinetic parameters were estimated using the WinNonlin ® software with non- compartment model analysis. The mean ± SD of maximum plasma concentration (C max ), the area under the plasma concentration-time curve from 0 to 48 h (AUC 0-last ) and the area under the plasma concentration-time curve from 0 to infinity (AUC 0-∞ ) of Ketipinor ® v.s. Seroquel ® were 632.27 ± 304.43 v.s. 638.83 ± 214.49 ng/ml; 2,625.21 ± 972.14 v.s. 2,511.82 ± 704.21 ng.h/ml and 2,640.25 ± 979.10 v.s. 2,526.45 ± 704.37 ng.h/ml, respectively. The time to reach C max (T max ) of Ketipinor ® and Seroquel ® were 1.34 ± 1.11 and 1.01 ± 0.63 h., respectively. The T max of Ketipinor ® was within the acceptance range of ±20% of the median T max of the reference product. The 90% confidence interval of the ratios of the log-transformed data of C max , AUC 0-last and AUC 0-∞ were 80.75 - 102.60%, 91.32 - 108.42% and 88.47 - 106.77%, respectively, which were within the acceptance range of 80.00 - 125.00%. Power of the test for C max , AUC 0-last and AUC 0-∞ were 92.16%, 96.34% and 95.96%, respectively. In conclusion, Ketipinor ® was bioequivalent to Seroquel ® in terms of both the rate and extent of absorption under fasting condition.