title: An improved LC-MS/MS method for quantitation of indapamide in whole blood: application for a bioequivalence study.
abstract: An improved LC-MS/MS method for the quantitation of indapamide in human whole blood was developed and validated. Indapamide-d3 was used as internal standard (IS) and liquid-liquid extraction was employed for sample preparation. LC separation was performed on Synergi Polar RP-column (50 × 4.6 mm i.d.; 4 µm) and mobile phase composed of methanol and 5 mm aqueous ammonium acetate containing 1 mm formic acid (60:40), at flow rate of 1 mL/min. The run time was 3.0 min and the injection volume was 20 μL. Mass spectrometric detection was performed using electrospray ion source in negative ionization mode, using the transitions m/z 364.0 → m/z 188.9 and m/z 367.0 → m/z 188.9 for indapamide and IS, respectively. Calibration curve was constructed over the range 0.25-50 ng/mL. The method was precise and accurate, and provided recovery rates >80% for indapamide and IS. The method was applied to determine blood concentrations of indapamide in a bioequivalence study with two sustained release tablet formulations. The 90% confidence interval for the geometric mean ratios for maximum concentration was 95.78% and for the area under the concentration-time curve it was 97.91%. The tested indapamide tablets (Eurofarma Laboratórios S.A.) were bioequivalent to Natrilix®, according to the rate and extent of absorption.
authors.affiliation: Eurofarma Laboratórios, Av. Vereador José Diniz 3465, 04603-003, São Paulo, SP, Brazil.
authors.forename: Guilherme Araújo
authors.initials: GA
authors.lastname: Pinto
authors.forename: Kátia Isabel Fercondini
authors.initials: KI
authors.lastname: Pastre
authors.forename: Karini Bruno
authors.initials: KB
authors.lastname: Bellorio
authors.forename: Leonardo
authors.initials: L
authors.lastname: de Souza Teixeira
authors.forename: Weidson Carlo
authors.initials: WC
authors.lastname: de Souza
authors.forename: Fernanda Crunivel
authors.initials: FC
authors.lastname: de Abreu
authors.forename: Fabiana Fernandes
authors.initials: FF
authors.lastname: de Santana E Silva Cardoso
authors.forename: Gerson Antônio
authors.initials: GA
authors.lastname: Pianetti
authors.forename: Isabela Costa
authors.initials: IC
authors.lastname: César
mesh_terms: D000293:Adolescent; D000328:Adult; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007190:Indapamide / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013810:Therapeutic Equivalency; D055815:Young Adult
chemical_list: D007190:Indapamide
keywords: LC-MS/MS; bioequivalence; indapamide; whole blood