ABSTRACT
Procedures for the extraction-spectrophotometric determination of tris(2-chloroethyl)amine, an alkylating agent known as a drug as well as a chemical warfare agent (nitrogen mustard HN-3), with 7 acid-base indicators of a triphenylmethane lactone type, phthaleins, were developed. Representatives of phthaleins without an oxygen bridge (thymolphthalein, o-cresolphthalein, naphtholphthalein) and with an oxygen bridge (fluorescein, 2',7'-dichlorofluorescein, eosin B and eosin Y) were used. The methods were based on the formation of ion pair complexes. Chloroform was used as a non-polar solvent for an extraction. The conditions to determine were optimized for the optimal pH of the buffer and the concentration of a phthalein as a reagent. The dependence on the reaction time in a water phase and the stoichiometry of extraction products were studied. The detection limits and the limits of the determination of separate procedures and conditional extraction constants were determined. Comparison with the spectrophotometric method of the group determination of alkyl halides and acyl halides using alkaline ethanol-water solution of thymolphthalein, the so-called T-135 agent, was conducted. While studying the selectivity, the possible interference of bis(2-chloroethyl)sulphide and 3 nitrogen mustards in the proposed procedures were verified. Copyright © 2016 John Wiley & Sons, Ltd.
Subject(s)
Alkylating Agents/isolation & purification , Chemical Warfare Agents/isolation & purification , Nitrogen Mustard Compounds/isolation & purification , Phenolphthaleins/chemistry , Alkylating Agents/analysis , Buffers , Chemical Warfare Agents/analysis , Hydrogen-Ion Concentration , Limit of Detection , Nitrogen Mustard Compounds/analysis , Spectrophotometry/methods , Water/analysisABSTRACT
Reactivation efficacy of three homologous and three isomeric series of pralidoxime-type reactivators with aldoxime group in position 2, 3 and 4 of the heterocycle was tested in reactivation of tabun-inhibited AChE. The experiments were performed with immobilized and stabilized porcine brain AChE. The enzyme activity was measured by Ellman method. Reactivation efficacy was determined by measurement of indicator fabric coloration intensity as a measure of AChE activity. Of the studied group of nine reactivators, isomers with the functional group in position 2 were the most effective. The highest value (30 %) for reactivation of inhibited AChE was found for 2PAE after treatment for 15 min at concentration 0.5 mg/cm(3). The efficacy of the isomers decreased in the order ortho > para > meta. No marked effect on the efficacy of the reactivators was observed on prolongation of the reactivation time. The reactivators efficacy decreased with decreasing concentration of their solutions.
Subject(s)
Acetylcholinesterase/drug effects , Cholinesterase Inhibitors/toxicity , Cholinesterase Reactivators/pharmacology , Organophosphates/toxicity , Pralidoxime Compounds/pharmacology , Animals , Isomerism , Pralidoxime Compounds/chemistry , SwineABSTRACT
OBJECTIVES: Quantification of efficacy of monopyridinium isomers and homologs derived from clinically used Pralidoxime within reactivation of acetylcholinesterase inhibited with organophosphorus nerve agents. METHODS: This work uses the colorimetric biosensor called Detehit - cotton cloth with immobilized enzyme acetylcholinesterase. Biosensor is based on the modificated Ellman's method. RESULTS: The highest reactivation was observed with sarin-inhibited acetylcholinesterase. Substantially lower reactivation was found with the cyclosarin-inhibited enzyme whereas AChE, inhibited by soman could not be effectively reactivated under the given conditions (enzyme inhibition for 2 minutes and subsequent treatment with the reactivator for 15 minutes). CONCLUSION: Our work gives comparison of efficacy of reactivators in dependence on the length of alkylene chain and position of aldoxime functional group. Evaluation of effectivity of aldoxime reactivators is provided by simple means. The method allows rapid in vitro evaluation of the reactivators without being disturbed by excess of the organophosphate or reactivator.
Subject(s)
Acetylcholinesterase/metabolism , Cholinesterase Inhibitors/toxicity , Cholinesterase Reactivators/pharmacology , Pralidoxime Compounds/chemistry , Pralidoxime Compounds/pharmacology , Biosensing Techniques , Cholinesterase Inhibitors/chemistry , Cholinesterase Reactivators/chemistry , Enzymes, Immobilized/antagonists & inhibitors , Enzymes, Immobilized/metabolism , Isomerism , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Oximes/chemistry , Oximes/pharmacology , Sarin/toxicity , Soman/toxicityABSTRACT
Reactivation with bis quaternary aldoxime HI-6, chemical formula 1-(2-hydroxyamino-methylpyridinium)-3-(4-carbamoylpyridinium)-2-oxapropane dichloride of immobilized enzyme acetylcholinesterase inhibited by nerve agent type "G" was studied. This aldoxime is effective in reactivation of sarin-inhibited acetylcholinesterase. Substantially lower reactivation potency was observed with cyclosarin-inhibited enzyme and almost no effect was found for that acetylcholinesterase is the enzyme complex. HI 6 is completely ineffective towards the soman-inhibited enzyme: After a 2-minute inhibition of the enzyme with soman no ability to define reactivator the inhibited enzymes and complexes.
Subject(s)
Acetylcholinesterase/metabolism , Chemical Warfare Agents/pharmacology , Cholinesterase Inhibitors/pharmacology , Cholinesterase Reactivators/pharmacology , Pyridinium Compounds/pharmacology , Animals , Biosensing Techniques , Brain/enzymology , Enzymes, Immobilized , Indicators and Reagents , Kinetics , Models, Chemical , Oximes , SwineABSTRACT
Using an immobilized acetylcholinesterase-tabun enzyme-inhibitor complex, the reactivation efficacy of a homologous series of bispyridinium reactivators with increasing length of the alkylene chain between the pyridinium rings has been studied. The number of the alkylene groups in the chain ranged from one to six. N,N'-Monomethylenebis(4-pyridiniumaldoxime) dibromide (MMB-4) and N,N'-trimethylenebis(4-pyridiniumaldoxime) dibromide (TMB-4) are the most efficient reactivators of the series.
Subject(s)
Acetylcholinesterase/drug effects , Cholinesterase Reactivators/pharmacology , Oximes/pharmacology , Pyridinium Compounds/pharmacology , Acetylcholinesterase/metabolism , Animals , Chemical Warfare Agents/toxicity , Cholinesterase Inhibitors/toxicity , Enzymes, Immobilized , Organophosphates/toxicity , Structure-Activity Relationship , SwineABSTRACT
ABSTRACT Efficacy of reactivators 2-PAM, TMB-4, HI-6, and toxogonin in reactivation of acetylcholinesterase inhibited by compound R-33 has been studied. The study was performed with acetylcholinesterase immobilized and stabilized on a cotton fabric and with an indicator paper with acetylthiocholine iodide and 5,5'-dithiobis(2-nitrobenzoic acid). The enzyme activity was determined by measurement of remission changes of the fabric surface, caused by reaction of the chromogenic reagent with products of enzymatic hydrolysis of the substrate. The most potent of the reactivators studied was 2-PAM at concentrations 0.5 mg.cm(-3) and 0.1 mg.cm(-3). Effectivity of this reactivator was over 20%. At these concentrations, reactivator HI-6 was less effective. Efficacy higher than that of 2-PAM was observed only after 20 min at concentrations 0.05 mg.cm(-3) and 0.01 mg.cm(-3). For TMB-4 and toxogonin the reactivation values were about 10% after 10 min, whereas after 15 or 20 min these reactivators were ineffective.
