title: Determination of memantine in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study.
abstract: A simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of memantine (I) in human plasma is presented. Sample preparation consisted of the addition of amantadine (II) as internal standard (IS), liquid-liquid extraction in basic conditions using a mixture of diethyl ether-chloroform (7:3, v/v) as extracting solvent, followed by centrifugation, solvent evaporation and sample reconstitution in methanol. Both I and II (internal standard) were analyzed using a C18 column and a mobile phase composed of methanol-water-formic acid (80:20:0.1, v/v/v). Eluted compounds were monitored using positive mode electrospray (ES) tandem mass spectrometry. The analyses were carried out by selected reaction monitoring (SRM) using the parent to daughter combinations of m/z 180>163 (memantine) and m/z 152>135 (amantadine). The peak areas from the analyte and IS were used for quantification of I. The achieved limit of quantification (LOQ) was 0.1 ng/mL; the assay exhibited a linear dynamic range of 0.1-50.0 ng/mL with a determination coefficient (r2) of at least 0.98. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of samples taken up to 320 h after oral administration of 20mg (two 10mg capsules) of I in healthy volunteers demonstrated the applicability to bioequivalence studies.
authors.affiliation: Core Clinical Research, 12914-160 Bragança Paulista, SP, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Almeida
authors.forename: D R
authors.initials: DR
authors.lastname: Campos
authors.forename: G
authors.initials: G
authors.lastname: Bernasconi
authors.forename: S
authors.initials: S
authors.lastname: Calafatti
authors.forename: F A P
authors.initials: FA
authors.lastname: Barros
authors.forename: M N
authors.initials: MN
authors.lastname: Eberlin
authors.forename: E C
authors.initials: EC
authors.lastname: Meurer
authors.forename: E G
authors.initials: EG
authors.lastname: Paris
authors.forename: J
authors.initials: J
authors.lastname: Pedrazzoli
mesh_terms: D000978:Antiparkinson Agents / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D008559:Memantine / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D015394:Molecular Structure; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013810:Therapeutic Equivalency
chemical_list: D000978:Antiparkinson Agents; D008559:Memantine