Combination of acetylcholinesterase inhibitors and NMDA receptor antagonists increases survival rate in soman-poisoned mice.

Organophosphorus nerve agents pose a global threat to both military personnel and civilian population, because of their high acute toxicity and insufficient medical countermeasures. Commonly used drugs could ameliorate the intoxication and overall medical outcomes. In this study, we tested the drugs able to alleviate the symptoms of Alzheimer's disease (donepezil, huperzine A, memantine) or Parkinson's disease (procyclidine). They were administered to mice before soman intoxication in terms of their: i) protection potential against soman toxicity and ii) influence on post-exposure therapy consisting of atropine and asoxime (also known as oxime HI-6). Their pretreatment effect was not significant, when administered alone, but in combination (acetylcholinesterase inhibitor such as denepezil or huperzine A with NMDA antagonist such as memantine or procyclidine) they lowered the soman toxicity more than twice. These combinations also positively influenced the efficacy of post-exposure treatment in a similar fashion; the combinations increased the therapeutic effectiveness of antidotal treatment. In conclusion, the most effective combination - huperzine A and procyclidine - lowered the toxicity three times and improved the post-exposure therapy efficacy more than six times. These results are unprecedented in the published literature.

Effect of Oxime Encapsulation on Acetylcholinesterase Reactivation: Pharmacokinetic Study of the Asoxime-Cucurbit[7]uril Complex in Mice Using Hydrophilic Interaction Liquid Chromatography-Mass Spectrometry.

Oxime-based molecules are used for the treatment of patients to reactivate acetylcholinesterase (AChE) function after organophosphate intoxication. However, their efficacy is limited by low penetration through the blood-brain barrier and fast elimination. In this work, the cucurbit[7]uril (CB[7]) carrier was used for the encapsulation of the clinical agent asoxime to enhance brain bioavailability and the treatment window. We present a pharmacokinetic study of asoxime and the asoxime-CB[7] complex in an in vivo mouse model. Ultrahigh-performance liquid chromatography with electrospray ionization-mass spectrometry detection was developed to determine asoxime and CB[7] in biological fluids and tissues after thorough optimization of chromatographic conditions. The dihydroxypropane-silica stationary phase using hydrophilic interaction liquid chromatography conditions provided the best chromatographic performance. The final method was validated and applied for the pharmacokinetic study of mouse plasma, urine, bile, liver, kidney, and brain samples at different times after administration of asoxime and the asoxime-CB[7] complex. The results showed a greater than 3-fold increase in the area under the curve (AUC) in the brain for asoxime administered as a complex with CB[7] relative to that for the administration of asoxime alone. The effectiveness of the treatment strategy was evaluated using a reactivation study and a functional observatory battery. Protection of brain AChE activity is crucial for saving human lives or reducing the consequences of poisoning. The asoxime administered as a complex increased the brain activity by approximately 30% compared to that with atropine alone. CB[7] coadministration improved the AChE activity by 11%, which agrees with the higher asoxime AUC assessed in the pharmacokinetic study.

Interaction of Cucurbit[7]uril with Oxime K027, Atropine, and Paraoxon: Risky or Advantageous Delivery System?

Antidotes against organophosphates often possess physicochemical properties that mitigate their passage across the blood-brain barrier. Cucurbit[7]urils may be successfully used as a drug delivery system for bisquaternary oximes and improve central nervous system targeting. The main aim of these studies was to elucidate the relationship between cucurbit[7]uril, oxime K027, atropine, and paraoxon to define potential risks or advantages of this delivery system in a complex in vivo system. For this reason, in silico (molecular docking combined with umbrella sampling simulation) and in vivo (UHPLC-pharmacokinetics, toxicokinetics; acetylcholinesterase reactivation and functional observatory battery) methods were used. Based on our results, cucurbit[7]urils affect multiple factors in organophosphates poisoning and its therapy by (i) scavenging paraoxon and preventing free fraction of this toxin from entering the brain, (ii) enhancing the availability of atropine in the central nervous system and by (iii) increasing oxime passage into the brain. In conclusion, using cucurbit[7]urils with oximes might positively impact the overall treatment effectiveness and the benefits can outweigh the potential risks.

Influence of experimental end point on the therapeutic efficacy of the antinicotinic compounds MB408, MB442 and MB444 in treating nerve agent poisoned mice - a comparison with oxime-based treatment.

Therapeutic efficacy of antidotal treatment of acute poisoning by nerve agents is generally assessed by the evaluation of LD50 values of nerve agents over 24 h following poisoning without or with a single administration of antidotal treatment. In this study, LD50 values of four nerve agents (sarin, soman, tabun and cyclosarin) for non-treated and treated poisoning were evaluated in mice for two experimental end points - 6 h and 24 h. While the efficacy of atropine or oxime-based antidotal treatment was the same regardless of the experimental end point, the therapeutic efficacy of all three newly developed bispyridinium non-oxime compounds (MB408, MB442, and MB444) was mostly slightly higher at the 6 h end point compared to the 24 h end point, although the therapeutic efficacy of MB compounds was not superior to oxime-based antidotal treatment. These results contrast with a study in guinea-pigs using a structurally-related compound, MB327, which showed a striking increase in protection at 6 h compared to 24 h. It is suggested that the disparity may be due to pharmacokinetic differences between the two animal species.

The evaluation of oxidative damage of DNA after poisoning with nerve agents.

The potency of three nerve agents (sarin, soman, tabun) to induce oxidative damage of DNA in lymphocytes, liver and brain during lethal or sublethal poisoning was investigated. The single strand breaks or oxidative base DNA damage was evaluated with the help of Comet assay and a specific enzyme able to detect oxidative bases of DNA (endonuclease III). While sarin and soman administered at sublethal doses corresponding to 50% of their LD50 values were not able to induce oxidative damage of DNA, their lethal dose (LD50) induced the significant increase of the number of oxidative bases in DNA of hepatocytes. In addition, tabun administered at lethal dose (LD50) induced significant increase of the number of single strand breaks and oxidative bases of DNA in glial cells isolated from pontomedullar brain region. Thus, some nerve agents were able to induce oxidative damage in the peripheral as well as central compartment but only in the case of severe poisoning caused by lethal doses of nerve agents. This non-cholinergic effect of nerve agents has probably consequences with nerve agents-induced hypoxic status during acute cholinergic crisis and it can contribute to their long-term toxic effects.

The Evaluation of the Reactivating and Neuroprotective Efficacy of Two Newly Prepared Bispyridinium Oximes (K305, K307) in Tabun-Poisoned Rats-A Comparison with Trimedoxime and the Oxime K203.

The ability of two newly developed oximes (K305, K307) to protect tabun-poisoned rats from tabun-induced inhibition of brain acetylcholinesterase, acute neurotoxic signs and symptoms and brain damage was compared with that of the oxime K203 and trimedoxime. The reactivating and neuroprotective effects of the oximes studied combined with atropine on rats poisoned with tabun at a sublethal dose were evaluated. The reactivating efficacy of a newly developed oxime K305 is lower compared to the reactivating efficacy of the oxime K203 and trimedoxime while the ability of the oxime K307 to reactivate tabun-inhibited acetylcholinesterase (AChE) in the brain roughly corresponds to the reactivating efficacy of the oxime K203 and it is slightly lower compared to trimedoxime. In addition, only one newly developed oxime (K307) combined with atropine was able to markedly decrease tabun-induced neurotoxicity although it did not eliminate all tabun-induced acute neurotoxic signs and symptoms. These results correspond to the histopathological evaluation of tabun-induced brain damage. Therefore, the newly developed oximes are not suitable for the replacement of commonly used oximes (especially trimedoxime) in the treatment of acute tabun poisonings.

A comparison of neuroprotective efficacy of two novel reactivators of acetylcholinesterase called K920 and K923 with the oxime K203 and trimedoxime in tabun-poisoned rats.

The ability of two newly developed bispyridinium oximes (K920, K923) to reduce tabun-induced acute neurotoxic signs and symptoms was compared with the oxime K203 and trimedoxime using a functional observational battery (FOB). The neuroprotective effects of the oximes studied combined with atropine on rats poisoned with tabun at a sublethal dose (130 µg/kg i.m.; 80% of LD50 value) were evaluated. Tabun-induced neurotoxicity was monitored by FOB at 2 h after tabun administration. The results indicate that all tested oximes combined with atropine enable tabun-poisoned rats to survive till the end of experiment while one non-treated tabun-poisoned rat died within 2 h. Both newly developed oximes (K920, K923) combined with atropine were able to markedly decrease tabun-induced neurotoxicity in the case of sublethal poisoning although they did not eliminate all tabun-induced acute neurotoxic signs and symptoms. Their ability to decrease tabun-induced acute neurotoxicity did not prevail the neuroprotective efficacy of trimedoxime and the oxime K203. Therefore, the newly developed oximes are not suitable for the replacement of currently available oximes (especially trimedoxime) in the treatment of acute tabun poisonings.

Dose Dependent Prophylactic Efficacy of 6-Chlorotacrine in Soman-Poisoned Mice.

AIM: The influence of the dose on the ability of promising newly prepared reversible inhibitor of acetylcholinesterase (6-chlorotacrine) to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was evaluated. METHODS: The evaluation of the effect of pharmacological pretreatment is based on the identification of changes of soman-induced toxicity that was evaluated by the assessment of its LD50 value and its 95% confidence limit using probit-logarithmical analysis of death occurring within 24 hrs after administration of soman. RESULTS: The dose of 6-chlorotacrine significantly influences the prophylactic efficacy of 6-chlorotacrine. Its highest dose was only able to significantly protect mice against acute toxicity of soman and increase the efficacy of antidotal treatment (atropine in combination with the oxime HI-6) of soman-poisoned mice. In addition, the highest dose of 6-chlorotacrine was significantly more effective to protect mice from soman poisoning than its lowest dose. CONCLUSION: These findings demonstrate the important influence of the dose of 6-chlorotacine on its prophylactic efficacy in the case of pharmacological pretreatment of soman poisoning in mice.

The Evaluation of Benefit of Newly Prepared Reversible Inhibitors of Acetylcholinesterase and Commonly Used Pyridostigmine as Pharmacological Pretreatment of Soman-Poisoned Mice.

AIM: The ability of four newly prepared reversible inhibitors of acetylcholinesterase (6-chlorotacrine, 7-phenoxytacrine, compounds 1 and 2) and currently used carbamate pyridostigmine to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was evaluated. METHODS: The evaluation of the effect of pharmacological pretreatment is based on the identification of changes of soman-induced toxicity that was evaluated by the assessment of its LD50 value and its 95% confidence limit using probitlogarithmical analysis of death occurring within 24 h after administration of soman. RESULTS: 6-chlorotacrine was only able to markedly protect mice against acute toxicity of soman. In addition, the pharmacological pretreatment with 6-chlorotacrine or compound 2 was able to increase the efficacy of antidotal treatment (the oxime HI-6 in combination with atropine) of soman-poisoned mice. The other newly prepared reversible inhibitors of acetylcholinesterase (7-phenoxytacrine, compound 1) as well as commonly used pyridostigmine did not influence the efficacy of antidotal treatment. CONCLUSION: These findings demonstrate that pharmacological pretreatment of somanpoisoned mice can be promising and useful in the case of administration of 6-chlorotacrine and partly compound 2.

Evaluation of the benefit of the bispyridinium compound MB327 for the antidotal treatment of nerve agent-poisoned mice.

The potency of the bispyridinium non-oxime compound MB327 [1,1'-(propane-1,3-diyl)bis(4-tert-butylpyridinium) diiodide] to increase the therapeutic efficacy of the standard antidotal treatment (atropine in combination with an oxime) of acute poisoning with organophosphorus nerve agents was studied in vivo. The therapeutic efficacy of atropine alone - or atropine in combination with an oxime, MB327, or both an oxime and MB237 - was evaluated by the determination of LD50 values of several nerve agents (tabun, sarin and soman) in mice with and without treatment. The addition of MB327 increased the therapeutic efficacy of atropine alone, and atropine in combination with an oxime, against all three nerve agents, although differences in the LD50 values only reached statistical significance for sarin. In conclusion, the addition of the compound MB327 to the standard antidotal treatment of acute poisonings with nerve agents was beneficial regardless of the chemical structure of the nerve agent, although at the dose employed, MB327 in combination with atropine, or atropine and an oxime, provided only a modest increase in protection ratio. These results from mice, and previous ones from guinea-pigs, provide consistent evidence for additional, albeit modest, efficacy resulting from the inclusion of the antinicotinic compound MB327 in standard antidotal therapy. Given the typically steep probit slope for the dose-lethality relationship for nerve agents, such modest increases in protection ratio could provide significant survival benefit.

A comparison of the reactivating and therapeutic efficacy of two novel bispyridinium oximes (K727, K733) with the oxime HI-6 and obidoxime in sarin-poisoned rats and mice.

The ability of two novel bispyridinium oximes K727 and K733 and currently available oximes (HI-6, obidoxime) to reactivate sarin-inhibited acetylcholinesterase and to reduce acute toxicity of sarin was evaluated. To investigate the reactivating efficacy of the oximes, the rats were administered intramuscularly with atropine and oximes in equitoxic doses corresponding to 5% of their LD50 values at 1 min after the intramuscular administration of sarin at a dose of 24 µg/kg (LD50). The activity of acetylcholinesterase was measured at 60 min after sarin poisoning. The LD50 value of sarin in non-treated and treated mice was assessed using probit-logarithmical analysis of death occurring within 24 h after intramuscular administration of sarin at five different doses. In vivo determined percentage of reactivation of sarin-inhibited rat blood, diaphragm and brain acetylcholinesterase showed that the potency of both novel oximes K727 and K733 to reactivate sarin-inhibited acetylcholinesterase roughly corresponds to the reactivating efficacy of obidoxime. On the other hand, the oxime HI-6 was found to be the most efficient reactivator of sarin-inhibited acetylcholinesterase. While the oxime HI-6 was able to reduce the acute toxicity of sarin >3 times, both novel oximes and obidoxime decreased the acute toxicity of sarin <2 times. Based on the results, we can conclude that the reactivating and therapeutic efficacy of both novel oximes K727 and K733 is significantly lower compared to the oxime HI-6 and, therefore, they are not suitable for the replacement of the oxime HI-6 for the antidotal treatment of acute sarin poisoning.

Natural Detoxification Capacity to Inactivate Nerve Agents Sarin and VX in the Rat Blood.

BACKGROUND: The method of continual determination of the rat blood cholinesterase activity was developed to study the changes of the blood cholinesterases following different intervetions. AIMS: The aim of this study is registration of cholinesterase activity in the rat blood and its changes to demonstrate detoxification capacity of rats to inactivate sarin or VX in vivo. METHODS: The groups of female rats were premedicated (ketamine and xylazine) and cannulated to a. femoralis. Continual blood sampling (0.02 ml/min) and monitoring of the circulating blood cholinesterase activity were performed. Normal activity was monitored 1-2 min and then the nerve agent was administered i.m. (2×LD50). Using different time intervals of the leg compression and relaxation following the agent injection, cholinesterase activity was monitored and according to the inhibition obtained, detoxification capacity was assessed. RESULTS: Administration of sarin to the leg, then 1 and 5 min compression and 20 min later relaxation showed that further inhibition in the blood was not observed. On the other hand, VX was able to inhibit blood cholinesterases after this intervention. CONCLUSIONS: The results demonstrated that sarin can be naturally detoxified on the contrary to VX. Described method can be used as model for other studies dealing with changes of cholinesterases in the blood following different factors.

The Evaluation of the Potency of Newly Developed Oximes (K727, K733) and Trimedoxime to Counteract Acute Neurotoxic Effects of Tabun in Rats.

AIM: The ability of two newly developed oximes (K727, K733) to reduce tabun-induced acute neurotoxic signs and symptoms was evaluated and compared with currently available trimedoxime in rats. METHODS: The neuroprotective effects of the oximes studied combined with atropine on Wistar rats poisoned with tabun at a lethal dose (380 µg/kg i.m.; 90% of LD50 value) were evaluated. Tabun-induced neurotoxicity was monitored by the functional observational battery consisting of 38 measurements of sensory, motor and autonomic nervous functions at 2 hours following tabun challenge. RESULTS: All tested oximes combined with atropine enable tabun-poisoned rats to survive till the end of experiment. Both newly developed oximes (K727, K733) combined with atropine were able to decrease tabun-induced neurotoxicity in the case of lethal poisoning although they did not eliminate all tabun-induced acute neurotoxic signs and symptoms. CONCLUSION: The ability of both novel bispyridinium oximes to decrease tabun-induced acute neurotoxicity was slightly lower than that of trimedoxime. Therefore, the newly developed oximes are not suitable for the replacement of commonly used oximes such as trimedoxime in the treatment of acute tabun poisonings.

The evaluation of the reactivating and therapeutic efficacy of two novel oximes (K361 and K378) in comparison with the oxime K203 and trimedoxime in tabun-poisoned rats and mice.

The potency of two newly developed oximes (K361 and K378) to reactivate tabun-inhibited cholinesterase and to reduce acute toxicity of tabun was compared with the oxime K203 and trimedoxime using in vivo methods. The study determining percentage of reactivation of tabun-inhibited diaphragm cholinesterase in poisoned rats showed that the reactivating efficacy of the oxime K378 is slightly lower than the reactivating potency of the oxime K203 and trimedoxime while the ability of the oxime K361 to reactivate tabun-inhibited cholinesterase is markedly lower compared with the oxime K203 and trimedoxime. In the brain, the potency of both newly developed oximes to reactivate tabun-inhibited cholinesterase was negligible. The therapeutic efficacy of both newly developed oximes roughly corresponds to their weak reactivating efficacy. Their potency to reduce acute toxicity of tabun was significantly lower compared with the oxime K203 as well as trimedoxime. In conclusion, the reactivating and therapeutic potency of both newly developed oximes does not prevail the effectiveness of the oxime K203 and trimedoxime and, therefore, they are not suitable for their replacement of commonly used oximes for the treatment of acute tabun poisoning.

Potent and reversible open-channel blocker of NMDA receptor derived from dizocilpine with enhanced membrane-to-channel inhibition.

N-methyl-D-aspartate receptors (NMDARs) play a significant role in developing several central nervous system (CNS) disorders. Currently, memantine, used for treating Alzheimer's disease, and ketamine, known for its anesthetic and antidepressant properties, are two clinically used NMDAR open-channel blockers. However, despite extensive research into NMDAR modulators, many have shown either harmful side effects or inadequate effectiveness. For instance, dizocilpine (MK-801) is recognized for its powerful psychomimetic effects due to its high-affinity and nearly irreversible inhibition of the GluN1/GluN2 NMDAR subtypes. Unlike ketamine, memantine and MK-801 also act through a unique, low-affinity "membrane-to-channel inhibition" (MCI). We aimed to develop an open-channel blocker based on MK-801 with distinct inhibitory characteristics from memantine and MK-801. Our novel compound, K2060, demonstrated effective voltage-dependent inhibition in the micromolar range at key NMDAR subtypes, GluN1/GluN2A and GluN1/GluN2B, even in the presence of Mg2+. K2060 showed reversible inhibitory dynamics and a partially trapping open-channel blocking mechanism with a significantly stronger MCI than memantine. Using hippocampal slices, 30 µM K2060 inhibited excitatory postsynaptic currents in CA1 hippocampal neurons by ∼51 %, outperforming 30 µM memantine (∼21 % inhibition). K2060 exhibited No Observed Adverse Effect Level (NOAEL) of 15 mg/kg upon intraperitoneal administration in mice. Administering K2060 at a 10 mg/kg dosage resulted in brain concentrations of approximately 2 µM, with peak concentrations (Tmax) achieved within 15 minutes. Finally, applying K2060 with trimedoxime and atropine in mice exposed to tabun improved treatment outcomes. These results underscore K2060's potential as a therapeutic agent for CNS disorders linked to NMDAR dysfunction.

A comparison of the reactivating efficacy of a novel bispyridinium oxime K203 with currently available oximes in VX agent-poisoned rats.

The ability of a novel bispyridinium oxime K203 to reactivate VX agent-inhibited acetylcholinesterase was compared with the reactivating efficacy of four commonly used oximes (obidoxime, trimedoxime, methoxime, HI-6) using in vivo model. Our results showed that the reactivating efficacy of the oxime HI-6 is higher than the reactivating efficacy of the other oximes studied including the oxime K203 although the differrences between the oxime HI-6 and some other oximes are not significant, especially in the blood. Based on the obtained data, we can conclude that the antidotal treatment involving the oxime HI-6 brings the higher benefit for the antidotal treatment of acute poisonings with VX agent than other oximes.

The evaluation of the reactivating and therapeutic efficacy of three novel bispyridinium oximes (K454, K456, K458) in comparison with the oxime K203 and trimedoxime in tabun-poisoned rats and mice.

The potency of three newly developed bispyridinium compounds (K454, K456, K458) to reactivate tabun-inhibited acetylcholinesterase and reduce tabun-induced lethal toxic effects was compared with the oxime K203 and trimedoxime using in vivo methods. The study determining percentage of reactivation of tabun-inhibited diaphragm and brain acetylcholinesterase in poisoned rats showed that the reactivating efficacy of all newly developed oximes is comparable with K203 but lower than the reactivating potency of trimedoxime in diaphragm. In the brain, their potency to reactivate tabun-inhibited acetylcholinesterase is lower compared with trimedoxime and the oxime K203. All three newly developed oximes were also found to be relatively effective in reducing lethal toxic effects in tabun-poisoned mice. Their therapeutic efficacy is consistent with the therapeutic potency of the oxime K203. On the other hand, their potency to reduce acute toxicity of tabun is significantly lower compared with trimedoxime. In conclusion, the reactivating and therapeutic potency of all three newly developed oximes does not prevail the effectiveness of the oxime K203 and trimedoxime and, therefore, they are not suitable for their replacement of commonly used oximes for the treatment of acute tabun poisoning.

The benefit of combination of oximes for the neuroprotective efficacy of antidotal treatment of sarin-poisoned rats.

The potency of the oxime HI-6 and two combinations of oximes (HI-6 + trimedoxime, HI-6 + K203) to reduce sarin-induced acute neurotoxic signs and symptoms was evaluated in this study. Sarin-induced neurotoxicity and the neuroprotective effects of atropine alone or in combination with HI-6 alone and HI-6 combined with trimedoxime or K203 in rats poisoned with sarin at a sublethal dose (108 µg/kg i.m.; 90% of LD(50) value) were monitored by a functional observatory battery (FOB) 24 h following sarin administration. The results indicate that both mixtures of oximes combined with atropine were able to survive sarin-poisoned rats 24 h following sarin administration while two non-treated sarin-poisoned rats and one sarin-poisoned rat treated with atropine alone or with atropine in combination with the oxime HI-6 died within 24 h following sarin poisoning. All types of antidotal treatment were able to decrease sarin-induced neurotoxic signs and symptoms but not completely. While atropine alone and atropine in combination with the oxime HI-6 were able to eliminate some sarin-induced neurotoxic signs and symptoms, the neuroprotective efficacy of both combinations of oximes with atropine was slightly higher. Thus, both tested combinations of oximes in combination with atropine bring a small benefit for the neuroprotective efficacy of antidotal treatment of acute sarin poisonings.

Combined approach to demonstrate acetylcholinesterase activity changes in the rat brain following tabun intoxication and its treatment.

Reactivation effects of K203 and currently available oximes (obidoxime, HI-6) in combination with atropine on acetylcholinesterase activities in the brain parts of rats poisoned with tabun were studied. The activity was determined by quantitative histochemical and biochemical methods correlating between them very well. The tabun-induced changes in acetylcholinsterase activity as well as in reactivation potency of reactivators used were different in various parts of the brain. Pontomedullar area seems to be important for observed changes following tabun intoxication and its treatment. From the oximes studied, the reactivation effect of K203 was comparable with obidoxime; HI-6 was ineffective. Combination of bio- and histochemical methods allow fine differentiation among the action of different oximes following tabun poisoning.

The ability of oxime mixtures to increase the reactivating and therapeutic efficacy of antidotal treatment of cyclosarin poisoning in rats and mice.

The reactivating and therapeutic efficacy of two combinations ofoximes (HI-6 + trimedoxime and HI-6 + K203) was compared with the effectiveness of antidotal treatment involving single oxime (HI-6, trimedoxime, K203) using in vivo methods. In vivo determined percentage of reactivation of cyclosarin-inhibited blood and tissue acetylcholinesterase in poisoned rats showed that the reactivating efficacy of both combinations of oximes is slightly higher than the reactivating efficacy of the most effective individual oxime in blood, diaphragm as well as in brain. Moreover, both combinations of oximes were found to be slightly more efficacious in the reduction of acute lethal toxic effects in cyclosarin-poisoned mice than the antidotal treatment involving single oxime. Based on the obtained data, we can conclude that the antidotal treatment involving chosen combinations of oximes brings a beneficial effect for its ability to counteract the acute poisoning with cyclosarin.