ABSTRACT
Nikethamide and lidocaine are often requested to be quantified simultaneously in forensic toxicological analysis. A simple reversed-phase high performance liquid chromatography (RP-HPLC) method has been developed for their simultaneous determination in human blood and cerebrospinal fluid. The method involves simple protein precipitation sample treatment followed by quantification of analytes using HPLC at 263 nm. Analytes were separated on a 5 microm Zorbax Dikema C18 column (150 mm x 4.60 mm, i.d.) with a mobile phase of 22:78 (v/v) mixture of methanol and a diethylamine-acetic acid buffer, pH 4.0. The mean recoveries were between 69.8 and 94.4% for nikethamide and between 78.9 and 97.2% for lidocaine. Limits of detection (LODs) for nikethamide and lidocaine were 0.008 and 0.16 microg/ml in plasma and 0.007 and 0.14 microg/ml in cerebrospinal fluid, respectively. The mean intra-assay and inter-assay coefficients of variation (CVs) for both analytes were less than 9.2 and 10.8%, respectively. The developed method was applied to blood sample analyses in eight forensic cases, where blood concentrations of lidocaine ranged from 0.68 to 34.4 microg/ml and nikethamide ranged from 1.25 to 106.8 microg/ml. In six cases cerebrospinal fluid analysis was requested. The values ranged from 20.3 to 185.6 microg/ml of lidocaine and 8.0 to 72.4 microg/ml of nikethamide. The method is simple and sensitive enough to be used in toxicological analysis for simultaneous determination of nikethamide and lidocaine in blood and cerebrospinal fluid.
Subject(s)
Chromatography, High Pressure Liquid/methods , Lidocaine/blood , Lidocaine/cerebrospinal fluid , Nikethamide/blood , Nikethamide/cerebrospinal fluid , Adult , Aged , Anesthetics, Local/blood , Anesthetics, Local/cerebrospinal fluid , Central Nervous System Stimulants/blood , Central Nervous System Stimulants/cerebrospinal fluid , Chromatography, High Pressure Liquid/instrumentation , Fatal Outcome , Forensic Medicine/methods , Humans , Male , Middle Aged , Reference Standards , Reproducibility of Results , Retrospective Studies , Sensitivity and SpecificitySubject(s)
Lung Diseases, Obstructive/blood , Nikethamide/blood , Aged , Chromatography, High Pressure Liquid , Humans , Male , Middle AgedABSTRACT
Following the intramuscular administration of nikethamide to a series of greyhounds, both plasma and urine excretion levels were obtained. A qualitative urine screening procedure for both nikethamide and its major metabolite has been devised. The method involves solvent extraction, thin-layer and a two-system gas chromatographic system.
