title: Development and validation of a high-performance liquid chromatography-electrospray ionization-MS/MS method for the simultaneous quantitation of levodopa and carbidopa in human plasma.
abstract: A sensitive and fast high-performance liquid chromatography-electrospray ionization-MS/MS method for the simultaneous quantitation of levodopa and carbidopa in human plasma was developed and validated. A simple protein precipitation step with perchloric acid was used for the cleanup of plasma, and methyldopa was added as an internal standard. The analyses were carried out using an ACE C(18) column (50 × 4.6 mm i.d.; 5 µm particle size) and a mobile phase consisting of 0.2% formic acid and acetonitrile (90:10). The triple-quadrupole mass spectrometer equipped with an electrospray source in positive mode was set up in the selective reaction monitoring mode to detect the ion transitions m/z 198.1 → m/z 107.0, m/z 227.2 → m/z 181.0, and m/z 212.1 → m/z 139.2 for levodopa, carbidopa, and methyldopa, respectively. The method was validated and proved to be linear, accurate, and precise over the range 50-5000 ng/mL for levodopa and 3-600 ng/mL for carbidopa. The proposed method was successfully applied in a pharmacokinetic study with a levodopa/carbidopa tablet formulation in healthy volunteers.
authors.affiliation: Instituto de Ciências Farmacêuticas, Alameda Coronel Eugênio Jardim 53, 74175-100, Goiânia, GO, Brazil. isaccesar@bol.com.br
authors.forename: Isabela Costa
authors.initials: IC
authors.lastname: César
authors.forename: Ricardo Martins Duarte
authors.initials: RM
authors.lastname: Byrro
authors.forename: Fabiana Fernandes
authors.initials: FF
authors.lastname: Santana E Silva Cardoso
authors.forename: Iram Moreira
authors.initials: IM
authors.lastname: Mundim
authors.forename: Leonardo
authors.initials: L
authors.lastname: Souza Teixeira
authors.forename: Sandro Antônio
authors.initials: SA
authors.lastname: Gomes
authors.forename: Ricardo Rodrigues
authors.initials: RR
authors.lastname: Bonfim
authors.forename: Gerson Antônio
authors.initials: GA
authors.lastname: Pianetti
mesh_terms: D000284:Administration, Oral; D002230:Carbidopa / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D008297:Male; D008750:Methyldopa / Q000097:blood / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013607:Tablets / Q000008:administration & dosage / Q000493:pharmacokinetics; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D013607:Tablets; D007980:Levodopa; D008750:Methyldopa; D002230:Carbidopa