Solid phase extraction for an improved assay of physostigmine in biological fluids.
A simple, selective and very sensitive assay is described for the quantification of physostigmine in blood, plasma and urine. The most appropriate solid phase column was selected after a systematic investigation of nine types of phase. The conditions for solid phase extraction were optimized using [3H]physostigmine so that the overall recoveries were greater than 90%. Physostigmine was retained on alkaline treated cyanopropyl columns and eluted into the minimum volume of methanol, obviating the need for an evaporation step. Extracted samples were quantified by HPLC with a three electrode coulometric detection system. The limit of detection was 50 pg/mL for a 0.5 mL plasma sample. The precision (CV) for 0.5 mL plasma samples containing 50 pg was 8.1%. Application of the method to plasma, blood and urine samples is presented.
Hurst
P R
PR
Department of Pharmacology, London Hospital Medical College, UK.
Whelpton
R
R
D002845:Chromatography / Q000379:methods*; D006801:Humans; D010830:Physostigmine / Q000032:analysis* / Q000097:blood / Q000652:urine; D014316:Tritium
D014316:Tritium; D010830:Physostigmine