Six novel brominated bis-pyridinium oximes were designed and synthesized to increase their nucleophilicity and reactivation ability of phosphorylated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Their pKa was valuably found lower to parent non-halogenated oximes. Stability tests showed that novel brominated oximes were stable in water, but the stability of di-brominated oximes was decreased in buffer solution and their degradation products were prepared and characterized. The reactivation screening of brominated oximes was tested on AChE and BChE inhibited by organophosphorus surrogates. Two mono-brominated oximes reactivated AChE comparably to non-halogenated analogues, which was further confirmed by reactivation kinetics. The acute toxicity of two selected brominated oximes was similar to commercially available oxime reactivators and the most promising brominated oxime was tested in vivo on sarin- and VX-poisoned rats. This brominated oxime showed interesting CNS distribution and significant reactivation effectiveness in blood. The same oxime resulted with the best protective index for VX-poisoned rats.

• Klíčová slova
• Cholinesterase, Nerve agent, Nucleophile, Organophosphate, Oxime, Reactivation,
• MeSH
• acetylcholinesterasa * metabolismus   účinky léků   MeSH
• butyrylcholinesterasa * metabolismus   MeSH
• chemické bojové látky toxicita   MeSH
• cholinesterasové inhibitory * toxicita   farmakologie   MeSH
• halogenace MeSH
• krysa rodu Rattus MeSH
• nervová bojová látka * toxicita   MeSH
• organothiofosforové sloučeniny * toxicita   MeSH
• oximy * farmakologie   chemie   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy * farmakologie   chemie   MeSH
• sarin * toxicita   MeSH
• stabilita léku MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa * MeSH
• butyrylcholinesterasa * MeSH
• chemické bojové látky MeSH
• cholinesterasové inhibitory * MeSH
• nervová bojová látka * MeSH
• organothiofosforové sloučeniny * MeSH
• oximy * MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy * MeSH
• sarin * MeSH
• VX MeSH Prohlížeč

The organophosphorus antidotes, so-called oximes, are able to restore the enzymatic function of acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) via cleavage of organophosphate from the active site of the phosphylated enzyme. In this work, the charged pyridinium oximes containing thiocarboxamide moiety were designed, prepared and tested. Their stability and pKa properties were found to be analogous to parent carboxamides (K027, K048 and K203). The inhibitory ability of thiocarboxamides was found in low µM levels for AChE and high µM levels for BChE. Their reactivation properties were screened on human recombinant AChE and BChE inhibited by nerve agent surrogates and paraoxon. One thiocarboxamide was able to effectively restore function of NEMP- and NEDPA-AChE, whereas two thiocarboxamides were able to reactivate BChE inhibited by all tested organophosphates. These results were confirmed by reactivation kinetics, where thiocarboxamides were proved to be effective, but less potent reactivators if compared to carboxamides.

• Klíčová slova
• Cholinesterase, inhibition, organophosphate, oxime, reactivation,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• organofosfáty chemická syntéza   chemie   farmakologie   MeSH
• oximy chemická syntéza   chemie   farmakologie   MeSH
• pyridinové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• sulfhydrylové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• sulfhydrylové sloučeniny MeSH

Certain AChE reactivators, asoxime, obidoxime, K027, K048, and K075, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure the different organs. As a continuation of previously published data, in this study, Wistar rats have sacrificed 24 hrs and 7 days after single im application of 0.1LD50, 0.5LD50 and 1.0LD50 of each reactivator, and examinated tissue samples were obtained for pathohistological and semiquantitative analysis. A severity of tissue alteration, expressed as different tissue damage scores were evaluated. Morphological structure of examinated tissues treated with of 0.1LD50 of all reactivators was comparable with the control group of rats. Moderate injuries were seen in visceral tissues treated with 0.5LD50 of asoxime, obidoxime and K027. Acute damages were enlarged after treatment with 0.5LD50 and 1.0LD50 of all reactivators during the next 7 days. The most prominent changes were seen in rats treated with 1.0LD50 of K048 and K075 (P < 0.001 vs. control and asoxime-treated group). All reactivators given by a single, high, unitary dose regimen, have an adverse effect not only on the main visceral tissue, but on the whole rat as well, but the exact mechanism of cellular injury remains to be confirmed in further investigation.

• MeSH
• biopsie MeSH
• chemické bojové látky škodlivé účinky   chemie   toxicita   MeSH
• histocytochemie MeSH
• krysa rodu Rattus MeSH
• LD50 MeSH
• molekulární struktura MeSH
• orgánová specificita MeSH
• oximy aplikace a dávkování   škodlivé účinky   chemie   toxicita   MeSH
• plíce účinky léků   metabolismus   patologie   MeSH
• vnitřnosti účinky léků   patologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• žaludek účinky léků   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické bojové látky MeSH
• oximy MeSH

Therapeutic application of newly developed oximes is limited due to their adverse effects on different tissues. Within this article, it has been investigated which morphological changes could be observed in Wistar rats after the treatment with increasing doses of selected acetyl cholinesterase reactivators - asoxime, obidoxime, K027, K048, and K075. Subsequently, heart, diaphragm and musculus popliteus were obtained for pathohistological and semiquantitative analysis 24 hrs and 7 days after im administration of a single dose of 0.1 LD50, 0.5 LD50, and 1.0 LD50 of each oxime. Different muscle damage score was based on an estimation scale from 0 (no damage) to 5 (strong damage). In rats treated with 0.1 LD50 of each oxime, muscle fibres did not show any change. The intensive degeneration was found in all muscles after treatment with 0.5 LD50 of asoxime and obidoxime, respectively. Acute toxic muscle injury was developed within 7 days following treatment with 0.5 LD50 and 1.0 LD50 of each oxime, with the highest values in K048 and K075 group (P < 0.001 vs. control and asoxime), respectively. The early muscle alterations observed in our study seem to contribute to the pathogenesis of the oxime-induced toxic muscle injury, which probably manifests as necrosis and/or inflammation.

• MeSH
• bránice účinky léků   zranění   MeSH
• kosterní svaly účinky léků   zranění   MeSH
• krysa rodu Rattus MeSH
• myozitida chemicky indukované   MeSH
• nekróza MeSH
• oximy toxicita   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny toxicita   MeSH
• srdce účinky léků   MeSH
• svaly účinky léků   patologie   MeSH
• testy akutní toxicity MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium) propane dibromide MeSH Prohlížeč
• 1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium)butane MeSH Prohlížeč
• K075 compound MeSH Prohlížeč
• oximy MeSH
• pyridinové sloučeniny MeSH

BACKGROUND: Based on in vitro and in vivo rat experiments, the newly developed acetylcholinesterase (AChE) reactivator, K203, appears to be much more effective in the treatment of tabun poisonings than currently fielded oximes. METHODS: To determine if this reactivating efficacy would extend to humans, studies were conducted in vitro using human brain homogenate as the source of AChE. The efficacy of K203 was compared with commercially available oximes; pralidoxime, obidoxime and asoxime (HI-6). RESULTS: Reactivation studies showed that K203 was the most effective reactivator with a second order kinetic constant (kr) of 2142 min- 1. M- 1, which was 51 times higher than that obtained for obidoxime (kr = 42 min- 1. M- 1). Both pralidoxime and asoxime (HI-6) failed to significantly reactivate tabun-inhibited human AChE. DISCUSSION: According to these results and previous studies, using K203, it appears that oxime K203 is the most effective reactivator of tabun-inhibited cholinesterase in several species including humans and should be considered as a possible medical countermeasure to tabun exposure.

• Klíčová slova
• Antidotes, Chemical warfare agents, Oxime, Poisoning, Reactivator, Treatment,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antidota metabolismus   MeSH
• cholinesterasové inhibitory metabolismus   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• mozek enzymologie   MeSH
• organofosfáty metabolismus   MeSH
• oximy metabolismus   MeSH
• pyridinové sloučeniny metabolismus   MeSH
• reaktivátory cholinesterasy metabolismus   MeSH
• simulace molekulového dockingu MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-(4-carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)but-2-ene MeSH Prohlížeč
• acetylcholinesterasa MeSH
• antidota MeSH
• cholinesterasové inhibitory MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč

The blood-brain barrier plays a vital role in the protection of the central nervous system. It is composed of endothelial cells with tight-junctions to limit the penetration of many endogenous and exogenous compounds, particularly hydrophilic xenobiotics. Nerve agents and pesticides are groups of compounds with high penetration potential into the central nervous system. However, oxime type antidotes are known to penetrate blood-brain barrier only in low concentration. The aim of presented study is to describe the pharmacokinetic profile of oxime K027 a novel antidote candidate. The main focus is on penetration of tested substance into the selected brain regions following time-dependent manner. The maximum concentration of the oxime K027 was attaining 15 and 30 min after i.m. application in plasma and brain tissue, respectively. The perfused brain tissue concentration was relatively high (10(-7) M order of magnitude) and depending on the brain region it was constant 15-60 min after application. The highest concentration was found in the frontal cortex 15 min after application while the lowest measured concentration was determined in the basal ganglia. This study showed that oxime K027 is able to achieve high concentration level in perfused brain tissue relatively quickly, but also demonstrated rapid clearance from the central nervous system. These results are probably due to low overall uptake of oxime K027 into the brain.

• MeSH
• časové faktory MeSH
• centrální nervový systém účinky léků   metabolismus   MeSH
• hematoencefalická bariéra účinky léků   metabolismus   MeSH
• krysa rodu Rattus MeSH
• mozek účinky léků   metabolismus   MeSH
• oximy metabolismus   farmakokinetika   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny metabolismus   farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium) propane dibromide MeSH Prohlížeč
• oximy MeSH
• pyridinové sloučeniny MeSH

• Klíčová slova
• acetylcholinesterase, antidote, nerve agent, organophosphates, prophylaxis, therapy,
• Publikační typ
• časopisecké články MeSH

Oximes in combination with atropine, are an integral part of the treatment of acute intoxications with organophosphorus insecticides or with the nerve agents such as tabun, sarin, soman, cyclosarin or VX. Organophosphorus compounds are extremely potent inhibitors of the enzyme acetylcholinesterase (AChE, 3.1.1.7). The pharmacological action of oximes is multiple: they are able to reactivate the inhibited AChE, but they affect acetylcholine release in peripheral and central cholinergic synapses, allosterically modulate the muscarinic receptors in peripheral and central synapses, and influence the nicotinic receptor-associated ion-channels. In our study, we have determined the acute toxicity of different structures of oximes after intramuscular application in mice. The acute toxicity of oximes is crucial for the assesment of a dose applied as a treatment for organophosphorus intoxications. We have tested 7 oximes of different structures (HS-6, K033, BI-6, MMB-4, K048, HI-6 and obidoxime ) and during our experiments we have observed the intoxication process including typical signs of intoxication, and times of death. K033 was the most toxic oxime with an LD50 of only 48 mg/kg, while the least toxic oxime - HI-6 - has an LD50 value of 671 mg/kg. All the oximes tested were of the bispyridinium type, with different length or shape of the connecting chain and positions of oxime groups at the pyridinium rings. All these structural features play an important role in biological activity of these compounds performed by their acute toxicity as well as by their reactivation potency.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• myši MeSH
• reaktivátory cholinesterasy aplikace a dávkování   chemie   toxicita   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• reaktivátory cholinesterasy MeSH

The influence of newly developed oximes, K027 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide] and K048 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) butane dibromide], or currently used oximes (pralidoxime, obidoxime, trimedoxime, HI-6) and anticholinergic drugs (atropine, benactyzine) on the ability of antidotal treatment to eliminate tabun-induced acute toxic effects was studied in mice. The therapeutical efficacy of trimedoxime and both newly developed oximes (K027, K048) is significantly higher than the potency of pralidoxime (regardless of the choice of anticholinergic drug), obidoxime (in the case of its combination with atropine) and the oxime HI-6 (in the case of its combination with benactyzine). All studied oximes with the exception of pralidoxime and the oxime HI-6, when combined with benactyzine, appear to be more efficacious in the elimination of toxic effects of the lethal dose of tabun than their combination with atropine. The findings support the hypothesis that the choice of acetylcholinesterase reactivators as well as the anticholinergic drug selection are important for the effectiveness of an antidotal mixture in the case of antidotal treatment of tabun-induced acute poisonings.

• MeSH
• antidota farmakologie   MeSH
• chemické bojové látky otrava   MeSH
• cholinergní antagonisté farmakologie   MeSH
• hodnocení léčiv MeSH
• LD50 MeSH
• lékové interakce MeSH
• myši MeSH
• organofosfáty antagonisté a inhibitory   MeSH
• otrava organofosfáty MeSH
• oximy farmakologie   MeSH
• reaktivátory cholinesterasy terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• antidota MeSH
• chemické bojové látky MeSH
• cholinergní antagonisté MeSH
• organofosfáty MeSH
• oximy MeSH
• reaktivátory cholinesterasy MeSH
• tabun MeSH Prohlížeč

In this study, the influence of antidotal treatment of tabun poisoning on cognitive function, in the case of low-level tabun exposure, was studied. The impairment of cognitive function was evaluated by the measurement of spatial learning and memory in rats poisoned with a sublethal dose of tabun and treated with atropine alone or in combination with newly developed oximes {K027 [1-(4-hydroxyiminomethyl- pyridinium)-3-(4-carbamoylpyridinium) propane dibromide] and K048 [1-(4-hydroxyimino- methylpyridinium)-3-(4-carbamoylpyridinium) butane dibromide]} or currently available oxime (trimedoxime), using the Morris water maze. While atropine alone caused an impairment of studied cognitive functions, the addition of an oxime to atropine contributes to the improvement of cognitive performance of treated tabun-poisoned rats regardless of the type of oxime. The differences in the ameliorative effects of oximes on atropine-induced mnemonic deficits were not significant. Therefore, each low-level nerve agent exposure should be treated by complex antidotal treatment consisting of anticholinergic drug and oxime.

• MeSH
• antagonisté muskarinových receptorů farmakologie   MeSH
• antidota farmakologie   MeSH
• atropin farmakologie   MeSH
• bludiště - učení účinky léků   MeSH
• časové faktory MeSH
• chování zvířat MeSH
• kognice účinky léků   MeSH
• krysa rodu Rattus MeSH
• lékové interakce MeSH
• organofosfáty farmakologie   MeSH
• oximy farmakologie   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reakční čas účinky léků   MeSH
• trimedoxim farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• 1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium) propane dibromide MeSH Prohlížeč
• antagonisté muskarinových receptorů MeSH
• antidota MeSH
• atropin MeSH
• organofosfáty MeSH
• oximy MeSH
• pyridinové sloučeniny MeSH
• tabun MeSH Prohlížeč
• trimedoxim MeSH