title: Practice of solid-phase extraction and protein precipitation in the 96-well format combined with high-performance liquid chromatography-ultraviolet detection for the analysis of drugs in plasma and brain.
abstract: C18 Empore 96-well extraction disc plates have been employed for the analysis of three drugs with different polarities in plasma in conjunction with HPLC-UV, rufinamide, ICL670 and an anticonvulsant agent (AA1) in an early stage of development. With the most polar compound (AA1), ion-pair extraction at pH 12 was applied. The method developed for the assay of AA1 in plasma was applied to its determination in brain using an Oasis HLB plate following homogenisation in a pH 7.4 buffer and protein precipitation with NaOH-ZnSO4, thereby saving time for method development. Protein precipitation in the 96-well format with filtration of the precipitate was applied to the determination of ICL670, a highly protein-bound compound (>99.5%), with a good recovery (78%). Reversed-phase chromatography was applied using a short 5 cm column packed with 3 microm particles for the determination of ICL670 and AA1 and two parallel columns (15 cm long) for the determination of rufinamide. The methods were used routinely, one plate per analysis day being processed, resulting in increase in sample throughput and saving in solvents.
authors.affiliation: Drug Metabolism and Pharmacokinetics, Novartis Pharma SA, Rueil-Malmaison, France.
authors.forename: M C
authors.initials: MC
authors.lastname: Rouan
authors.forename: C
authors.initials: C
authors.lastname: Buffet
authors.forename: L
authors.initials: L
authors.lastname: Masson
authors.forename: F
authors.initials: F
authors.lastname: Marfil
authors.forename: H
authors.initials: H
authors.lastname: Humbert
authors.forename: G
authors.initials: G
authors.lastname: Maurer
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000032:analysis / Q000097:blood; D001565:Benzoates / Q000032:analysis / Q000097:blood; D001923:Brain Chemistry; D011232:Chemical Precipitation; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D000077588:Deferasirox; D015394:Molecular Structure; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000097:blood; D011137:Polystyrenes; D051381:Rats; D012117:Resins, Synthetic; D014230:Triazoles / Q000032:analysis / Q000097:blood
chemical_list: D000927:Anticonvulsants; D001565:Benzoates; D004364:Pharmaceutical Preparations; D011137:Polystyrenes; D012117:Resins, Synthetic; D014230:Triazoles; C003771:Amberlite XAD-2 resin; D000077588:Deferasirox; C079703:rufinamide