title: Concentrations of L-dopa in plasma and plasma ultrafiltrates.
abstract: A sensitive and specific procedure is described for the determination of therapeutically relevant concentrations of L-dopa in plasma and plasma ultrafiltrates (free fraction) by high performance liquid chromatography with electrochemical detection. In plasma samples from healthy adult subjects (n = 15) spiked with L-dopa (500 micrograms l-1) the free fraction averaged 76 +/- = 8% (range 61-84%). Free fraction values increased by 38% with increasing plasma concentrations of L-dopa from 100-5000 micrograms 1-1. L-dopa free fraction was not affect by the presence of 3-O-methyl-dopa at concentrations up to 10,000 micrograms l-1.
authors.affiliation: Servizio di Analisi Biochimico Cliniche, IRCCS Fondazione Mondino, Pavia, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Rizzo
authors.forename: M
authors.initials: M
authors.lastname: Memmi
authors.forename: R
authors.initials: R
authors.lastname: Moratti
authors.forename: G
authors.initials: G
authors.lastname: Melzi d'Eril
authors.forename: E
authors.initials: E
authors.lastname: Perucca
mesh_terms: D000328:Adult; D000978:Antiparkinson Agents / Q000097:blood*; D001798:Blood Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D007980:Levodopa / Q000097:blood*; D011485:Protein Binding; D014462:Ultrafiltration
chemical_list: D000978:Antiparkinson Agents; D001798:Blood Proteins; D007980:Levodopa