title: An HPLC-DAD method for the simultaneous quantification of opicapone (BIA 9-1067) and its active metabolite in human plasma.
abstract: Opicapone (BIA 9-1067) is a novel catechol-O-methyltransferase inhibitor presently under clinical development as an adjuvant in the pharmacotherapy of Parkinson's disease. This report describes the development and validation of a bioanalytical assay for the simultaneous quantification of opicapone and its active metabolite (BIA 9-1079) in human plasma. The method herein reported is based on high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and the sample preparation consists of a plasma protein precipitation step followed by liquid-liquid extraction. Chromatographic separation of the analytes (opicapone and BIA 9-1079) and the internal standard (tamoxifen) was achieved in less than 10 min on a reversed-phase C18 column at 25 °C by applying a gradient elution program using a mobile phase composed of 0.05 M monosodium phosphate solution adjusted to pH 2.45 (A) and acetonitrile (B) pumped at 0.8 mL min(-1). Opicapone and the internal standard were monitored at 271 nm while BIA 9-1079 was assessed at 257 nm. Calibration curves of both analytes were linear (r(2) ≥ 0.997) in the concentration range of 25-3000 ng mL(-1) and their limits of quantification were established to be 25 ng mL(-1). The overall precision did not exceed 13.2% and the accuracy was within ±11.1%. Several drugs potentially co-administered with opicapone were tested and they did not interfere at the retention times of the analytes (opicapone and BIA 9-1079) and internal standard. The method was then successfully applied for quantifying opicapone and its active metabolite (BIA 9-1079) in plasma samples obtained from a healthy subject enrolled in a clinical trial.
authors.affiliation: Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
authors.forename: Daniela
authors.initials: D
authors.lastname: Gonçalves
authors.forename: Gilberto
authors.initials: G
authors.lastname: Alves
authors.forename: Ana
authors.initials: A
authors.lastname: Fortuna
authors.forename: Patrício
authors.initials: P
authors.lastname: Soares-da-Silva
authors.forename: Amílcar
authors.initials: A
authors.lastname: Falcão
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006801:Humans; D059625:Liquid-Liquid Extraction; D010069:Oxadiazoles / Q000032:analysis / Q000097:blood* / Q000737:chemistry; D013629:Tamoxifen / Q000032:analysis / Q000097:blood* / Q000737:chemistry
chemical_list: D010069:Oxadiazoles; D013629:Tamoxifen; C549349:opicapone