High-performance liquid chromatographic method for the simultaneous determination of pentisomide and its major metabolite N-desisopropylpentisomide in plasma, urine and tissues using solid-phase extraction.
A rapid, sensitive and selective high-performance liquid chromatographic method for the simultaneous determination of pentisomide and its major metabolite desisopropylpentisomide in plasma, urine and tissues has been developed. The method for plasma samples, urine samples and tissue samples, after homogenizing with 50% ethanol, involves extraction of samples via activated Bond-Elut C8 disposable columns with methanol at pH 10 after addition of internal standard, and initially on column washing of samples at pH 10 with water and acetonitrile. The obtained methanolic extract is evaporated to dryness under nitrogen at 25 degrees C; the sample residue is then reconstituted in mobile phase and an aliquot of this solution is injected into the liquid chromatograph. Separation is performed using a Nova-Pak C18 4 microns particle size column operating in combination with radial compression separation unit and a methanol-water-di-sec.-butylamine-phosphoric acid (40:60:0.5:0.2, v/v) pH 3.5 mobile phase with ultraviolet detection at 258 nm. Endogenous substances or a variety of drugs concomitantly used in pentisomide therapy, with the exception of disopyramide, do not interfere with the assay. The mean recovery of pentisomide and desisopropylpentisomide from plasma and urine and from tissues is more than 91 and 86%, respectively. The limit of detection of the assay is 10 ng/ml for both drugs. The intra- and inter-day coefficient of variation for replicate analyses of spiked plasma samples is less than 7 and 8%, respectively. Mean steady-state plasma levels of pentisomide and desisopropylpentisomide in patients on chronic oral therapy are reported.
Forensic and Clinical Applications of Solid Phase Extraction
Introduction to Solid Phase Extraction Silica-Based Solid Phase Extraction The Chemistry of Bonded Silicas Bonded Phase Sorbent Synthesis Strategies for the Use of Solid Phase Extraction Optimizing Solid Phase Extraction Methods Separation of Analytes from Their Matrices Solid Phase Extraction Troubleshooting Drug Methods for the Toxicology Lab Selected Solid Phase Extraction Applications in Drug Analysis General Methods for Drug Isolation Chemical Derivatization Appendix A: Glossary Appendix B: Reagents Appendix C: Preparation of Solutions and Buffers Appendix D: Milliequivalent and Millimode Calculations Appendix E: Selected Solvent Polarity and Property Scale Appendix F: Buffers for Solid Phase Extraction Appendix G: pKa Reference for Solid Phase Extraction Appendix H: RapidTrace(R) Operation Guide Appendix I: Further Reading
Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromatography-mass spectrometry in plants producing crooked calf disease.
The major alkaloids of lupin plants producing crooked calf disease were identified by tandem gas chromatography-mass spectrometry and infrared analysis. The gas chromatography peak invariably present in teratogenic plants proved to be anagyrine. A minor but irregular contaminant of the peak was α-isolupanine. Other alkaloids present but apparently not associated with crooked calf disease were lupanine and two others that were probably epimethoxylupanine and 5,6-dehydrolupanine.