title: Evaluation and routine application of the novel restricted-access precolumn packing material Alkyl-Diol Silica: coupled-column high-performance liquid chromatographic analysis of the photoreactive drug 8-methoxypsoralen in plasma.
abstract: A fully automated coupled-column HPLC method for on-line sample processing and determination of the photoreactive drug 8-methoxypsoralen (8-MOP) in plasma has been developed. The method is based on the novel internal-surface reversed-phase precolumn packing materials Alkyl-Diol Silica (ADS). This new family of restricted-access materials has a hydrophilic, electroneutral outer particle surface and a hydrophobic internal pore surface. The supports tolerate the direct and repetitive injection of proteinaceous fluids such as plasma and allow a classical C18-, C8- or C4-reversed-phase partitioning at the internal (pore) surface. The total protein load, i.e. the lifetime of the precolumn used in this study (C8-Alkyl-Diol Silica, 25 microns, 25 x 4 mm I.D.), exceeds more than 100 ml of plasma. 8-MOP was detected by its native fluorescence (excitation 312 nm, emission 540 nm). Validation of the method revealed a quantitative and matrix-independent recovery (99.5-101.3% measured at five concentrations between 21.3 and 625.2 ng of 8-MOP per milliliter of plasma), linearity over a wide range of 8-MOP concentrations (1.2-3070 ng of 8-MOP/ml, r = 0.999), low limits of detection (0.39 ng of 8-MOP/ml) and quantitation (0.79 ng of 8-MOP/ml) and a high between-run (C.V. 1.47%, n = 10) and within-run (C.V. 1.33%, n = 10) reproducibility. This paper introduces coupled-column HPLC as a suitable method for on-site analysis of drug plasma profiles (bedside-monitoring).
authors.affiliation: Institut für Klinische Chemie, Ludwig-Maximilians-Universität, München, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Vielhauer
authors.forename: A
authors.initials: A
authors.lastname: Rudolphi
authors.forename: K S
authors.initials: KS
authors.lastname: Boos
authors.forename: D
authors.initials: D
authors.lastname: Seidel
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008730:Methoxsalen / Q000097:blood* / Q000627:therapeutic use; D010778:Photochemotherapy; D015203:Reproducibility of Results; D012822:Silicon Dioxide
chemical_list: C095072:alkyl-diol silica; D012822:Silicon Dioxide; D008730:Methoxsalen