title: Determination of unbound vismodegib (GDC-0449) concentration in human plasma using rapid equilibrium dialysis followed by solid phase extraction and high-performance liquid chromatography coupled to mass spectrometry.
abstract: A rapid equilibrium dialysis (RED) assay followed by a solid phase extraction (SPE) high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the quantitative determination of unbound vismodegib in human plasma was developed and validated. The equilibrium dialysis was carried out using 0.3 mL plasma samples in the single-use plate RED system at 37°C for 6h. The dialysis samples (0.1 mL) were extracted using a Strata-X-C 33u Polymeric Strong Cation SPE plate and the resulting extracts were analyzed using reverse-phase chromatography and positive electrospray ionization (ESI) mass spectrometry. The standard curve, which ranged from 0.100 to 100 ng/mL for vismodegib, was fitted to a 1/x(2) weighted linear regression model. The lower limit of quantitation (LLOQ, 0.100 ng/mL) was sufficient to quantify unbound concentrations of vismodegib after dialysis. The intra-assay precision of the LC-MS/MS assay, based on the four analytical QC levels (LLOQ, low, medium and high), was within 7.7% CV and inter-assay precision was within 5.5% CV. The assay accuracy, expressed as %Bias, was within ±4.0% of the nominal concentration values. Extraction recovery of vismodegib was between 77.9 and 84.0%. The assay provides a means for accurate assessment of unbound vismodegib plasma concentrations in clinical studies.
authors.affiliation: Drug Metabolism and Pharmacokinetics, Genentech, South San Francisco, CA 94080, USA. yuzhongd@gene.com
authors.forename: Yuzhong
authors.initials: Y
authors.lastname: Deng
authors.forename: Harvey
authors.initials: H
authors.lastname: Wong
authors.forename: Richard A
authors.initials: RA
authors.lastname: Graham
authors.forename: Wenbin
authors.initials: W
authors.lastname: Liu
authors.forename: Heuy-shin
authors.initials: HS
authors.lastname: Shen
authors.forename: Yao
authors.initials: Y
authors.lastname: Shi
authors.forename: Laixin
authors.initials: L
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Meng
authors.forename: Vikram
authors.initials: V
authors.lastname: Malhi
authors.forename: Xiao
authors.initials: X
authors.lastname: Ding
authors.forename: Brian
authors.initials: B
authors.lastname: Dean
mesh_terms: D000704:Analysis of Variance; D000813:Anilides / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification / Q000493:pharmacokinetics; D000970:Antineoplastic Agents / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D056148:Chromatography, Reverse-Phase; D003956:Dialysis / Q000379:methods*; D004355:Drug Stability; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D011485:Protein Binding; D011725:Pyridines / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000813:Anilides; D000970:Antineoplastic Agents; C538724:HhAntag691; D011725:Pyridines