Organophosphorus compounds (OP) make up an important class of inhibitors, mostly employed as pesticides, even as chemical weapons. These toxic substances act through the inhibition of the acetylcholinesterase (AChE) enzyme, which results in elevated synaptic acetylcholine (ACh) levels, leading to serious adverse effects under the cholinergic syndrome. Many reactivators have been developed to combat the toxic effects of these AChE inhibitors. In this line, the oximes highlight because of their good reactivating power of cholinesterase enzymes. To date, no universal antidotes can reactivate AChE inhibited by any OP agent. This review summarizes the intoxication process by neurotoxic OP agents, along with the development of reactivators capable of reversing their effects, approaching aspects like the therapeutic and toxicological profile of these antidotes. Computational methods and conscious in vitro studies, capable of significantly predicting the toxicological profile of these drug candidates, might support the process of development of these reactivators before entering in vivo studies in animals, and then clinical trials. These approaches can assist in the design of safer and more effective molecules, reducing related cost and time for the process.

• MeSH
• acetylcholinesterasa chemie   MeSH
• antidota * farmakologie   terapeutické užití   chemie   MeSH
• cholinesterasové inhibitory toxicita   MeSH
• organofosforové sloučeniny MeSH
• oximy terapeutické užití   toxicita   MeSH
• reaktivátory cholinesterasy * terapeutické užití   toxicita   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Oxime-based acetylcholinesterase reactivators (briefly oximes) regenerate organophosphate-inactivated acetylcholinesterase and restore its function. Poor blood-brain-barrier passage and fast elimination from blood limit their actual use in treatment of patients exposed to organophosphates. Previous in vitro results implicated further testing of cucurbit[7]uril as a delivery vehicle for bisquaternary oximes. The present paper focuses on cell toxicity, in vivo safety and influence of cucurbit[7]uril on oxime pharmacokinetics and pharmacodynamics. Neither the K027 nor the complex caused any cell toxicity, changes in blood biochemistry or hepato- or nephrotoxicity in tested concentrations. The encapsulation of K027 increased and accelerated the blood-brain-barrier penetration. The peripheral oxime exposure also increased, supporting the suggestion that cucurbit[7]uril protects the circulating oxime from rapid renal clearance. Contrary to the comparable in vitro reactivation power of K027 and the encapsulated K027, we failed to confirm this in vivo. In theory, this might result from the non-specific binding of molecules to the cucurbit[7]uril or the interaction of K027 with cucurbit[7]uril being too strong for acetylcholinesterase reactivation. Precise explanation requires additional in silico, in vitro and also in vivo experiments.

• MeSH
• acetylcholinesterasa krev   metabolismus   MeSH
• buňky A549 MeSH
• buňky Hep G2 MeSH
• erytrocyty účinky léků   enzymologie   MeSH
• GPI-vázané proteiny krev   metabolismus   MeSH
• hodnocení rizik MeSH
• imidazoly aplikace a dávkování   farmakokinetika   toxicita   MeSH
• injekce intramuskulární MeSH
• lidé MeSH
• maximální tolerovaná dávka MeSH
• mozek účinky léků   enzymologie   MeSH
• myši inbrední ICR MeSH
• oximy aplikace a dávkování   farmakokinetika   toxicita   MeSH
• přemostěné cyklické sloučeniny aplikace a dávkování   farmakokinetika   toxicita   MeSH
• pyridinové sloučeniny aplikace a dávkování   farmakokinetika   toxicita   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakokinetika   toxicita   MeSH
• tkáňová distribuce MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• atropin chemie   MeSH
• hematoencefalická bariéra MeSH
• imidazoly chemie   MeSH
• myši MeSH
• oximy chemie   MeSH
• paraoxon chemie   toxicita   MeSH
• počítačová simulace MeSH
• přemostěné cyklické sloučeniny chemie   MeSH
• pyridinové sloučeniny chemie   MeSH
• reaktivátory cholinesterasy chemie   toxicita   MeSH
• simulace molekulového dockingu MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The major function of compounds with an oxime moiety attached to a quarternary nitrogen pyridinium ring is to reactivate acetylcholinesterase inhibited by organophosphorus agent (OP). However, other oxime mechanisms (e.g. modulation of cholinergic or glutamatergic receptor) may be involved in the recovery. The main disadvantage of positively charged reactivators is their low ability to penetrate into the brain although crossing the blood brain barrier could be supported via increasing the dose of administered oxime. Thus, this study presents maximal tolerated doses (MTD) for marketed oximes (TMB-4, MMB-4, LüH-6, HI-6, 2-PAM) and the most promising K-oximes (K027, K048, K203) which can be used in OP therapy in the future. No signs of sarin intoxication were observed in mice treated with 100% MTD of HI-6 in contrast to those treated with atropine and only 5% LD50 of HI-6. 100% MTD of HI-6 resulted in levels of 500 μM and 12 μM in plasma and brain, respectively. This concentration is by a far margin safe with respect to direct effects on neuronal cell viability and, on the other hand, does not have any effects on central NMDA receptors or central nACh receptors. However, a weak antimuscarinic activity in case of LüH-6 and a weak peripheral antinicotinic action in case of TMB-4 and 2-PAM could be observed at their respective 100% MTD dose. These high doses, represented by MTD, are, however, irrelevant to clinical practice since they led to mild to moderate toxic side effects. Therefore, we conclude that clinically used doses of marketed oxime reactivators have no significant direct pharmacological effect on the tested receptors.

• MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• křečci praví MeSH
• kur domácí MeSH
• lidé MeSH
• maximální tolerovaná dávka * MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• organofosforové sloučeniny toxicita   MeSH
• oximy aplikace a dávkování   toxicita   MeSH
• pralidoximové sloučeniny aplikace a dávkování   toxicita   MeSH
• pyridinové sloučeniny aplikace a dávkování   toxicita   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   toxicita   MeSH
• viabilita buněk účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

K-oximes were developed as modern drug candidates acting as AChE reactivators. In this study, it has been investigated which interspecies and intergender differences changes could be observed in Wistar rats and Swiss mice, both genders, after the treatment with increasing doses of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, and K075. After the 24 h, a number of died animals was counted and the median lethal dose (LD50) for each oxime was calculated. By using the intramuscular route of administration, asoxime and K027 had the least toxicity in female rats (640.21 mg/kg and 686.08 mg/kg), and in female mice (565.75 mg/kg and 565.74 mg/kg), respectively. Moreover, asoxime and K027 showed 3, 4 or 8 times less acute toxicity in comparison to K048, obidoxime and K075, respectively. Beyond, K075 had the greatest toxicity in male rats (81.53 mg/kg), and in male mice (57.34 mg/kg), respectively. Our results can help to predict likely adverse toxic effects, target organ systems and possible outcome in the event of massive human overexposure, and in establishing risk categories or in dose selection for the initial repeated dose toxicity tests to be conducted for each oxime.

• MeSH
• acetylcholinesterasa chemie   metabolismus   MeSH
• krysa rodu rattus MeSH
• LD50 MeSH
• myši MeSH
• obidoxim chlorid toxicita   MeSH
• oximy toxicita   MeSH
• potkani Wistar MeSH
• prekurzory léčiv toxicita   MeSH
• reaktivátory cholinesterasy chemie   metabolismus   toxicita   MeSH
• testy akutní toxicity metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• analýza dat MeSH
• bránice enzymologie   MeSH
• GPI-vázané proteiny metabolismus   MeSH
• maximální tolerovaná dávka MeSH
• oximy farmakologie   toxicita   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny farmakologie   toxicita   MeSH
• reaktivátory cholinesterasy farmakologie   toxicita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The development of acetylcholinesterase reactivators, i.e., antidotes against organophosphorus poisoning, is an important goal of defense research. The aim of this study was to compare cytotoxicity and chemical structure of five currently available oximes (pralidoxime, trimedoxime, obidoxime, methoxime, and asoxime) together with four perspective oximes from K-series (K027, K074, K075, and K203). The cytotoxicity of tested substances was measured using two methods - colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and impedance based real-time cytotoxicity assay - in three different cell lines (HepG2, ACHN, and NHLF). Toxicity was subsequently expressed as toxicological index IC50. The tested compounds showed different cytotoxicity ranging from 0.92 to 40.06 mM. In HepG2 cells, K027 was the least and asoxime was the most toxic reactivator. In ACHN and NHLF cell lines, trimedoxime was the compound with the lowest adverse effects, whereas the highest toxicity was found in methoxime-treated cells. The results show that at least five structural features affect the reactivators' toxicity such as the number of oxime groups in the molecule, their position on pyridinium ring, the length of carbon linker, and the oxygen substitution or insertion of the double bond into the connection chain. Newly synthetized oximes with IC50 ≥ 1 mM evaluated in this three cell lines model might appear suitable for further testing.

• MeSH
• alternativy testů na zvířatech MeSH
• buňky Hep G2 MeSH
• fibroblasty účinky léků   MeSH
• inhibiční koncentrace 50 MeSH
• LD50 MeSH
• lidé MeSH
• molekulární struktura MeSH
• oximy chemie   toxicita   MeSH
• preklinické hodnocení léčiv MeSH
• reaktivátory cholinesterasy chemie   toxicita   MeSH
• viabilita buněk účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: In the last decade, the concept of uncharged reactivators potentially able to penetrate the CNS has been introduced as an alternative to the classic charged oxime reactivators. However, this concept brings with it several associated drawbacks such as higher lipophilicity, difficulty in administration, lower affinity to cholinesterases, and higher toxicity risk. OBJECTIVE: In this study, we compare data obtained for a set of five classic charged reactivators and a set of three recently published uncharged oximes supplemented by two novel ones. METHODS: This time, we used only in silico prediction and in vitro approaches. RESULTS: Our data showed that tested uncharged oximes have low affinity for cholinesterases, do not possess high reactivation potency, and certainly represent a greater toxicity risk due to higher lipophilicity. We assume that balanced physicochemical properties will be required for the successful treatment of OP poisoning. Nevertheless, the compound meeting such criteria and pinpointed in silico (K1280) failed in this particular case. CONCLUSION: From the presented data, it seems that the concept of uncharged reactivators will have to be modified, at least to improve the bioavailability and to satisfy requirements for in vivo administration.

• MeSH
• antidota chemická syntéza   farmakologie   toxicita   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   farmakologie   toxicita   MeSH
• hematoencefalická bariéra účinky léků   MeSH
• krysa rodu rattus MeSH
• myši MeSH
• organofosfáty toxicita   MeSH
• otrava organofosfáty farmakoterapie   MeSH
• oximy chemická syntéza   farmakologie   toxicita   MeSH
• paraoxon toxicita   MeSH
• počítačová simulace MeSH
• reaktivátory cholinesterasy chemická syntéza   farmakologie   toxicita   MeSH
• sarin toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The reactivating and therapeutic efficacy of two newly developed oximes (K305, K307) was compared with the oxime K203 and trimedoxime using in vivo methods The study determining percentage of reactivation of tabun-inhibited acetylcholinesterase in the peripheral as well as central nervous system (diaphragm, brain) in tabun-poisoned rats showed that the reactivating efficacy of both newly developed oximes is lower compared to the reactivating efficacy of the oxime K203 and trimedoxime. The therapeutic efficacy of all oximes studied roughly corresponds to their reactivating efficacy. While the ability of the oxime K305 to reduce acute toxicity of tabun in mice is approaching to the therapeutic efficacy of trimedoxime, the ability of another novel bispyridinium oxime K307 to reduce acute toxicity of tabun is significantly lower compared to trimedoxime and the oxime K203. Thus, the reactivating and therapeutic efficacy of both examined 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.

• MeSH
• acetylcholinesterasa účinky léků   MeSH
• antidota aplikace a dávkování   farmakologie   toxicita   MeSH
• atropin aplikace a dávkování   farmakologie   toxicita   MeSH
• bránice enzymologie   MeSH
• modely u zvířat MeSH
• mozek enzymologie   účinky léků   MeSH
• mutantní kmeny myší MeSH
• nervová bojová látka farmakologie   chemie   toxicita   MeSH
• organofosfáty farmakologie   toxicita   MeSH
• oximy * farmakologie   chemie   klasifikace   MeSH
• potkani Wistar MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakologie   toxicita   MeSH
• trimedoxim farmakologie   chemie   klasifikace   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

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.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• bránice účinky léků   enzymologie   MeSH
• chemické bojové látky otrava   MeSH
• cholinesterasové inhibitory toxicita   MeSH
• inbrední kmeny myší MeSH
• krysa rodu rattus MeSH
• mozek účinky léků   enzymologie   MeSH
• myši MeSH
• organofosfáty toxicita   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny toxicita   MeSH
• reaktivátory cholinesterasy toxicita   MeSH
• trimedoxim toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH