Steady-state pharmacokinetics and bioequivalence study of quetiapine fumarate film-coated tablets 300 mg in adult schizophrenic patients

Abstract

Quetiapine is a dibenzothiazepine derivative approved for the treatment of schizophrenia and related psychoses. The objective of the present study was to design and evaluate the bioequivalence between quetiapine fumarate film-coated tablets of Dr. Reddy’s Laboratories Ltd., Hyderabad, India (test) and Seroquel^® tablets (containing quetiapine) of AstraZeneca Pharmaceuticals LP Wilmington, DE, USA (reference). It was a two-way crossover steady-state multiple dose study in 54 adult schizophrenic patients under fasting conditions. Quetiapine was analyzed in plasma samples by using a validated liquid chromatographic mass spectrometry (LC-MS/MS) method. The pharmacokinetic parameters were estimated by noncompartmental method and mean (±SD) of C_max,ss (ng/mL) for test and reference products were 1436.5 (±810.2) and 1413.1 (±905.5), respectively. The mean (±SD) of AUC_τ,ss (ng·h/mL) for test and reference products were 6949.8 (±3879.8) and 6532.2 (±4279.4), respectively. The ratio of least square means and its 90% confidence interval for C_max,ss and AUC_τ,ss were found to be within bioequivalence limits 80.00–125.00%. In conclusion, test product was bioequivalent to the reference product in terms of both rate and extent of absorption under steady-state conditions.

Keywords::

• Quetiapine
• bioequivalence
• WinNonlin
• LC-MS/MS
• schizophrenia
• intrapatient variability

Acknowledgments

The authors thank Dr. Reddy’s Laboratories Limited, Hyderabad, India for giving permission to write this paper and to use in-house data.

Declaration of interest

All the authors are employees of Dr. Reddy’s Laboratories Limited, Hyderabad, India.