Sensitive detection of brucine an anti-metastatic drug for hepatocellular carcinoma at carbon nanotubes - nafion composite based biosensor.

A neoteric approach for the electrochemical analysis of brucine in biological environment has been developed. The glassy carbon electrode modified with single walled carbon nanotubes and nafion composite film is delineated for the first time to determine brucine employing square wave voltammetry. The quantification of brucine at physiological pH 7.2 manifests remarkable performance at the developed biosensor. The effect of several operational parameters has been studied in the present investigation. Under optimized conditions, a dynamic linear range from 1nM to 8µM with a high sensitivity of 340.8µAµM-1 and limit of detection corresponding to 0.11nM was achieved. The interfering effect of some coexisting metabolites on the current response of brucine has been reported. The method was successfully applied for the detection of brucine in traditional pharmaceutical formulations. The biological relevance of the present method has been demonstrated by the analysis of the alkaloid in human serum and urine samples. The analytical utility was further assessed by the selective determination of brucine in Strychnos nux-vomica seeds exhibiting considerable potential as a diagnostic tool.

Ionic liquid-based electromembrane extraction and its comparison with traditional organic solvent based electromembrane extraction for the determination of strychnine and brucine in human urine.

An ionic liquid-based electromembrane extraction (IL-EME) method was presented, and its performance was compared with 2-ethylnitrobenzene (ENB) based EME for the determination of strychnine and brucine in human urine. For the two methods, the fundamental extraction parameters such as supported liquid membrane, voltage, extraction time, pH values of sample solution and acceptor solution, temperature and salting-out effect were separately optimized. IL-EME provided 96- and 122-fold enrichment factors for strychnine and brucine, respectively, which were better than those obtained in EME (83- and 86-fold, respectively). The calibration curves were linear over the ranges of 20-720 µg L(-1) for strychnine and 20-640 µg L(-1) for brucine with the correlation coefficients higher than 0.9950. The repeatability of EME and IL-EME were evaluated by five parallel experiments giving the relative standard deviations of 5.12-6.98%. As the results indicated, compared with ENB based EME, the proposed IL-EME is more reliable and could provide better extraction performance for the determination of strychnine and brucine in human urine.

Metabolism of brucine: the important metabolic pathways of dihydroindole-type alkaloid for excretion in rats.

BACKGROUND: Brucine is a widely prescribed glycine antagonist, but a complete understanding of its metabolic pathway is still lacking. The present work represents the first investigation of in vivo metabolism of brucine in rats using LC-ESI-ion trap-TOF-MS. RESULTS: A total of 12 Phase I and five Phase II metabolites were tentatively identified. Brucine can be metabolized by hydrolysis, demethylation and methoxylation, in addition to diverse oxidations in a Phase I manner followed by glucuronidation in Phase II metabolism. Both the renal and biliary routes were observed for the excretion of brucine and its metabolites. CONCLUSION: Our results update the metabolism and disposition data on brucine, which provides basic information for better understanding of the pharmacological and toxicological activities of brucine-containing medicines.

[Quantitative determination of strychnine in blood and urine by gas chromatography with mass-selective detector].

A method for the quantitative determination of strychnine in biological fluids by gas chromatography--mass spectrometry is proposed. The preparation of samples for the analysis included extraction of strychnine from blood and urine with the use of AccuBond(II) EVIDEX cartridges for solid-phase extraction and SPEC MP3 disks respectively. The efficiency of extraction was estimated at 0.05 mg/l for blood and 0.02 mg/l for urine. The detection limit was 0.10 mg/l in blood and 0.05 mg/l in urine.

Rapid and sensitive determination of strychnine and brucine in human urine by capillary electrophoresis with field-amplified sample stacking.

A simple, rapid, sensitive and low-cost method using capillary electrophoresis (CE) coupled with field-amplified sample stacking (FASS) has been developed and validated for the simultaneous determination of strychnine and brucine residues in human urine. Before sample loading, a water plug (3.5 kPa, 3 s) was injected to contain sample cations and to permit FASS. Electrokinetic injection at a voltage (20 kV, 25 s) was then used to introduce cations. Separation was performed using 20 mM acetate buffer (pH 3.8) with an applied voltage of 20 kV. The calibration curves were linear over a range of 8.00-2.56 infinity 10(2) ng/mL (r = 0.9995) for strychnine and 10.0-3.20 x 10(2) ng/mL (r = 0.9999) for brucine. Extraction recoveries in urine were greater than 79.6 and 82.8% for strychnine and brucine, respectively, with an RSD of less than 4.9%. The detection limits (signal-to-noise ratio 3) for strychnine and brucine were 2.00 and 2.50 ng/mL, respectively. A urine sample from one healthy female volunteer (26 years old, 50 kg) was pretreated and analyzed. Strychnine and brucine levels in urine could be detected 24 h after administration. On these grounds, this method was feasible for application to preliminary screening of trace levels of abused drugs for both doping control and forensic analysis.

Simultaneous determination of five toxic alkaloids in body fluids by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

A novel analytical method was developed and validated for the rapid and simultaneous analysis of five toxic alkaloids: Brucine, Strychnine, Ephedrine, Aconitine and Colchicine, in blood and urine using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (HPLC-ESI-MRM) mode. The linear range was 0.05-50.0 ng mL(-1) for Brucine, 0.1-50.0 ng mL(-1) for Strychnine and Ephedrine, 0.01-10.0 ng mL(-1) for Aconitine and Colchicine. The limits of quantification for Brucine, Strychnine, Ephedrine, Aconitine and Colchicine were found to be 0.03, 0.05, 0.20, 0.05, 0.01 ng mL(-1), respectively. The average extraction recoveries in urine ranged from 96.0 to 114.0% and in whole blood were 94.0 to 113.0%. The intra-day and inter-day RSDs were less than 8.3 and 10.6%, respectively. The five alkaloids could be well separated within 7 min in a single run. The established method should be suitable for the determination of trace alkaloids in body fluids.

Application of high performance capillary electrophoresis on toxic alkaloids analysis.

We employed CE to identify mixtures of the toxic alkaloids lappaconitine, bullatine A, atropine sulfate, atropine methobromide, scopolamine hydrobromide, anisodamine hydrobromide, brucine, strychnine, quinine sulfate, and chloroquine in human blood and urine, using procaine hydrochloride as an internal standard. The separation employed a fused-silica capillary of 75 microm id x 60 cm length (effective length: 50.2 cm) and a buffer containing 100 mM phosphate and 5% ACN (pH 4.0). The sample was injected in a pressure mode and the separation was performed at a voltage of 16 kV and a temperature of 25 degrees C. The compounds were detected by UV absorbance at wavelengths of 195 and 235 nm. All the ten alkaloids were separated within 16 min. The method was validated with regard to precision (RSD), accuracy, sensitivity, linear range, LOD, and LOQ. In blood and urine samples, the detection limits were 5-40 ng/mL and linear calibration curves were obtained over the range of 0.02-10 microg/mL. The precision of intra- and interday measurements was less than 15%. Electrophoretic peaks could be identified either by the relative migration time or by their UV spectrum.

Hollow fiber-based liquid-phase microextraction combined with on-line sweeping for trace analysis of Strychnos alkaloids in urine by micellar electrokinetic chromatography.

A new method for the enrichment of Strychnos alkaloids in biological samples via liquid-phase microextraction (LPME) based on porous polypropylene hollow fibers combined with on-line sweeping in micellar electrokinetic chromatography (MEKC) was developed. Strychnos alkaloids were first extracted from urine sample which was adjusted to alkaline conditions (0.5 mol l(-1) NaOH). The unionized analytes were subsequently extracted into 1-octanol impregnated in the pores of hollow fibers, and then into an acidic acceptor solution (100 mmol l(-1) H3PO4) inside the hollow fiber. The extract was analyzed directly by on-line sweeping in MEKC. In the method, the compound berberine was used as the internal standard (I.S.) for the improvement of the experimental reproducibility. The calibration curve was linear over a range of 20-200 ng ml(-1) for both strychnine and brucine in human urine sample, with a correlation coefficient of 0.996 and 0.997, respectively. The detection limits (S/N=3:1) for strychnine and brucine were 1 and 2 ng ml(-1), respectively. The LPME-sweeping method has been successfully applied to the analysis of strychnine and brucine in real urine sample, indicating that LPME-sweeping-MEKC is a promising combination for analysis of basic drugs present at low levels in some biological matrices.

Quantitative LC-MS determination of strychnine in urine after ingestion of a Strychnos nux-vomica preparation and its consequences in doping control.

A simple, fast and sensitive method for the quantitative determination of strychnine residues in urine has been developed and validated. The method consists of a liquid-liquid extraction step with ethyl acetate at pH 9.2, followed by LC-MS/MS in positive atmospheric pressure chemical ionization (APCI)-mode. The method is linear in the range of 1-100 ng/mL and allows for the determination of strychnine at sub-toxicological concentrations. The accuracy of the method ranged from 1.3% to 4.4%. The method was used to determine the excretion profile of strychnine after the ingestion of an over-the-counter herbal preparation of Strychnos nux-vomica. Each volunteer ingested a dose equivalent to 380 micro g of strychnine. This dose is lower than the prescription dose but results in the detection of strychnine for over 24-h post administration. Maximum detected urinary concentrations ranged from 22.6 to 176 ng/mL. The results of this study show that the use of this type of preparation by athletes can lead to a positive doping case.

[Concentration and determination of strychnine alkaloid in biological fluids].

OBJECTIVE: To establish a new method for determination of strychnine alkaloid in biological fluids based on molecularly imprinted polymers. METHODS: A strychnine molecularly imprinted monolithic column was prepared by in-situ molecularly imprinted technique. The polymer was filled to a 1cm column, and a method was developed to concentrate and determine strychnine alkaloids in biological fluids. RESULTS: the limit of detection of the method was 4.9 ng, and the recoveries were more than 92%. The relative standard deviations were smaller than 6.59%. The linear correlation coefficients of standard curves were 0.999 1 and 0.9966 respectively. This method was applied to concentrate and determine strychnine in plasma and urine of poisoned rabbit. CONCLUSION: The new method could concentrate and simultaneously determine strychnine alkaloids in biological fluids, and it was applied to forensic toxicological analysis.

Concentration and determination of strychnine alkaloid in biological fluids / 法医学杂志

OBJECTIVE@#To establish a new method for determination of strychnine alkaloid in biological fluids based on molecularly imprinted polymers.@*METHODS@#A strychnine molecularly imprinted monolithic column was prepared by in-situ molecularly imprinted technique. The polymer was filled to a 1cm column, and a method was developed to concentrate and determine strychnine alkaloids in biological fluids.@*RESULTS@#the limit of detection of the method was 4.9 ng, and the recoveries were more than 92%. The relative standard deviations were smaller than 6.59%. The linear correlation coefficients of standard curves were 0.999 1 and 0.9966 respectively. This method was applied to concentrate and determine strychnine in plasma and urine of poisoned rabbit.@*CONCLUSION@#The new method could concentrate and simultaneously determine strychnine alkaloids in biological fluids, and it was applied to forensic toxicological analysis.

[Strychnine poisoning]. / Strychninvergiftung.

HISTORY AND ADMISSION FINDINGS: A 46-year-old man presented two hours after ingestion of about 250 mg strychnine with severe violent, generalized convulsions, triggered by external stimuli. During the convulsion-free periods there were no abnormal signs in the physical examination. INVESTIGATION: The presence of strychnine was confirmed by urine analysis with gas chromatography-mass spectrometry. TREATMENT AND COURSE: Because diazepam as anticonvulsant of choice was not effective in abating the convulsions the patient was intubated. A combination with midazolam, fentanyl and pancuronium was effective in controlling the convulsions. The patient was discharged from ICU on day three. CONCLUSION: Fatal outcome of strychnine poisoning demands an aggressive management with early intubation, control of muscle tremors and prevention of rhabdomyolisis and renal failure.

Enhanced elimination of theophylline, phenobarbital and strychnine from the bodies of rats and mice by squalane treatment.

Our previous study suggested that squalane would be a good candidate for an antidote to reduce the toxicity of drug ingested accidentally at a high dose by enhancing the drug elimination from the body. In the present study, we investigated whether squalane given orally could enhance the elimination of theophylline, phenobarbital and strychnine which were administered parenterally to rats or mice. Squalane increased the fecal excretion of theophylline and reduced the serum level of the drug in rats. Squalane accelerated the fecal excretion of strychnine in mice. These results suggest that squalane may stimulate more the elimination of neutral (theophylline) or basic (strychnine) drugs which should be present in unionized form in intestinal lumen, than that of acidic drugs.

A case of concomitant ethanol and strychnine intoxication.

The authors describe a patient presenting with both ethanol intoxication and important strychnine poisoning. The diagnosis and treatment of strychnine poisoning are discussed. The authors emphasize the need of careful urine screening for drugs and toxic products in all ethanol-intoxicated patients.

A new high performance liquid chromatography (HPLC) method for the quantitation of strychnine in urine and tissue extracts.

A high performance liquid chromatography (HPLC) method was developed for the quantitation of strychnine in urine of children with nonketotic hyperglycinaemia and other developmental disorders treated with the alkaloid. Mobile and stationary phases were polar, i.e. methanol-water-330 g/kg ammonia (volumes, 85 ml + 14.2 ml + 0.8 ml) and LiChrosorb Si-60, 7 microns. Brucine was the internal standard. Extraction was performed by the Extrelut technique. At strychnine nitrate concentrations in urine of 21, 126, and 70 micrograms/l, recovery was 92.1 +/- 8.7, 98.1 +/- 2.7, and 102.5 +/- 2.7%. A child with nonketotic hyperglycinaemia under continued strychnine treatment excreted 1 to 13.6% of the daily dose unmetabolized in urine. The method was also suitable for the estimation of unreacted strychnine in tissue extracts. The fast disappearance in vitro of strychnine from a guinea pig liver preparation was confirmed.