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.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory aplikace a dávkování   toxicita   MeSH
• enzymatické testy MeSH
• hematoencefalická bariéra metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• hydrofobní a hydrofilní interakce MeSH
• imidazoly chemie   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nosiče léků chemie   MeSH
• otrava organofosfáty farmakoterapie   MeSH
• oximy aplikace a dávkování   farmakokinetika   MeSH
• plocha pod křivkou MeSH
• přemostěné cyklické sloučeniny chemie   MeSH
• pyridinové sloučeniny aplikace a dávkování   farmakokinetika   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakokinetika   MeSH
• sarin aplikace a dávkování   toxicita   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Oxime cholinesterase reactivators (oximes) are used to counteract organophosphate intoxication. Charged oximes are administered via intramuscular or intravenous injection when the majority of dose is unmetabolized and is excreted as urine. In this study, the effects of selected double charged oximes were determined in the HK-2 cell line as a model for renal toxicity screening. Some effects on dehydrogenase activity were found for obidoxime, asoxime (syn. HI-6), K027, and K203. The effects of K868 and K869 were found to be unreliable due to rapid degradation of both chlorinated oximes in the assay medium, resulting for K868 in an isoxazole-pyridinium product.

• MeSH
• buněčné linie MeSH
• ledviny účinky léků   metabolismus   MeSH
• lidé MeSH
• molekulární struktura MeSH
• oximy aplikace a dávkování   škodlivé účinky   chemie   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   škodlivé účinky   chemie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem 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

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

Organophosphates, useful agents as pesticides, also represent a serious danger due to their high acute toxicity. There is indication that oximes, when administered before organophosphate exposure, can protect from these toxic effects. We have tested at equitoxic dosage (25% of LD01 ) the prophylactic efficacy of five experimental (K-48, K-53, K-74, K-75, K-203) and two established oximes (pralidoxime and obidoxime) to protect from mortality induced by the organophosphate paraoxon. Mortalities were quantified by Cox analysis and compared with those observed after pretreatment with a strong acetylcholinesterase inhibitor (10-methylacridine) and after the FDA-approved pretreatment compound pyridostigmine. All nine tested substances statistically significantly reduced paraoxon-induced mortality. Best protection was conferred by the experimental oxime K-48, reducing the relative risk of death (RR) to 0.10, which was statistically significantly superior to pyridostigmine (RR = 0.31). The other oximes reduced the RR to 0.13 (obidoxime), 0.20 (K-203), 0.21 (K-74), 0.24 (K-75) and 0.26 (pralidoxime), which were significantly more efficacious than 10-methylacridine (RR = 0.65). These data support the hypothesis that protective efficacy is not primarily due to cholinesterase inhibition and indicate that the tested experimental oximes may be considered promising alternatives to the established pretreatment compound pyridostigmine.

• MeSH
• analýza přežití MeSH
• LD50 MeSH
• obidoxim chlorid aplikace a dávkování   farmakologie   MeSH
• ochranné látky aplikace a dávkování   farmakologie   MeSH
• paraoxon chemie   toxicita   MeSH
• potkani Wistar MeSH
• pralidoximové sloučeniny aplikace a dávkování   farmakologie   MeSH
• proporcionální rizikové modely MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The misuse of organophosphate compounds still represents a current threat worldwide. Treatment of poisoning with organophosphates (OPs) remains unsatisfactorily resolved despite the extensive investment in research in academia. There are no universal, effective and centrally-active acetylcholinesterase (AChE) reactivators to countermeasure OP intoxication. One major obstacle is to overcome the blood-brain barrier (BBB). The central compartment is readily accessible by the OPs which are lipophilic bullets that can easily cross the BBB, whereas first-line therapeutics, namely oxime-based AChE reactivators and atropine, do not cross or do so rather slowly. The limitation of oxime-based AChE reactivators can be ascribed to their chemical nature, bearing a positive charge which is essential either for their AChE affinity or their reactivating potency. The aim of this article is to review the methods for targeting the brain by oxime reactivators that have been developed so far. Approaches using prodrugs, lipophilicity enhancement, or sugar-based oximes have been rather unsuccessful. However, other strategies have been more promising, such as the use of nanoparticles or co-administration of the reactivator with efflux transporter inhibitors. Encouraging results have also been associated with intranasal delivery, but research in this field is still at the beginning. Further research of auspicious approaches is inevitable.

• MeSH
• biologický transport MeSH
• cholinesterasové inhibitory otrava   MeSH
• lidé MeSH
• mozek metabolismus   MeSH
• otrava organofosfáty farmakoterapie   metabolismus   MeSH
• oximy aplikace a dávkování   farmakokinetika   terapeutické užití   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakokinetika   terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy 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

Standard treatment of organophosphorus compounds (OPs) poisoning includes administration of an anti-muscarinic (atropine), anticonvulsive (diazepam) and acetylcholinesterase reactivator (oxime). From a wide group of newly synthesized oximes, oxime K027 and oxime K203 seem to be perspective compounds in some specific OPs intoxication. The available in vitro and in vivo preclinical data indicate that both oximes may be considered for potential human use. The main aim of this study was to establish plasmatic concentration curves of both oximes after intramuscular (i.m.) and intragastric (i.g.) application with subsequent pharmacokinetic analysis and study distribution after (i.m.) application on a non-rodent animal model (experimental pigs; 1500mg/animal). According to the results, both oximes had similar Cmax (K027: 106±19μg/mL and K203: 111±8μg/mL) in Tmax 19±5min, respectively, in 22±3min. Bioavailability of oxime K027 calculated as AUCtotal (8389±1024minμg/mL) was halved compared to oxime K203 (16938±795minμg/mL). The highest concentration from peripheral tissues was found in the kidney and lung, but the brain concentrations stay very low, the plasma/brain ratio being approximately 1%. The applied doses were derived from the recommendation where it is possible to use three autoinjectors to save human life. The results provide us with knowledge about the pharmacokinetics and distribution of these new oximes and may help us to better estimate the human pharmacokinetic profile.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• aplikace orální MeSH
• injekce intramuskulární MeSH
• orgánová specificita MeSH
• oximy aplikace a dávkování   krev   farmakokinetika   MeSH
• plocha pod křivkou MeSH
• pyridinové sloučeniny aplikace a dávkování   krev   farmakokinetika   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   krev   farmakokinetika   MeSH
• Sus scrofa MeSH
• tkáňová distribuce MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: Oxime HI-6 DMS (dimethanesulfonate) is an asymmetric bis-pyridinium aldoxime and essential acetylcholinesterase (AChE) reactivator. The high effectiveness is due to its wide spectrum of therapeutic activity against different structures of nerve agents. Aim of this study was to compare plasma time profiles and tissue distribution (to delimitation of potential toxicity risks) after its intramuscular (i.m.) and intragastric (i.g.) administration to experimental pigs. METHODS: The study entered female Landrace pigs (Sus scrofa f. domestica), 4-5 months old animals, 29 +/- 3.2 kg of body weight. Before the HI-6 DMS administration (i.m. injection or i.g. using a gastric tube), vena auricularis was cannulated (under general anaesthesia) for collection of blood samples. The tissue distribution study was carried out at expected t-max. Concentrations of HI-6 DMS in blood plasma and other tissue samples were detected by means of HPLC method. RESULTS: Fast absorption after i.m. administration, relatively slow absorption and no even elimination after i.g. administration were found. Tissue distribution showed low accumulation in the liver, but a higher content in the kidneys and high concentrations in the brain and gastrointestinal wall. CONCLUSIONS: Plasma time profiles after i.g. administration has a prolonged pharmacokinetics. Tissue distribution study showed potential side effects to the stomach due to a higher accumulation of HI-6 in this tissue after i.g. administration but not after a standard i.m. administration. Higher content of HI-6 in the kidneys after i.m. administration suggests the main way of the oxime elimination.

• MeSH
• oximy aplikace a dávkování   farmakokinetika   škodlivé účinky   MeSH
• pyridinové sloučeniny aplikace a dávkování   farmakokinetika   škodlivé účinky   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakokinetika   škodlivé účinky   MeSH
• Sus scrofa krev   metabolismus   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH

x

• Klíčová slova
• K378, K458, HI-6,
• MeSH
• antidota aplikace a dávkování   MeSH
• atropin aplikace a dávkování   MeSH
• chemické bojové látky otrava   MeSH
• cholinesterasové inhibitory terapeutické užití   MeSH
• kombinovaná farmakoterapie MeSH
• krysa rodu rattus MeSH
• LD50 MeSH
• myši MeSH
• neuroprotektivní látky aplikace a dávkování   MeSH
• obidoxim chlorid aplikace a dávkování   MeSH
• oximy * aplikace a dávkování   chemie   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny aplikace a dávkování   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   MeSH
• sarin * otrava   toxicita   MeSH
• statistika jako téma MeSH
• testy akutní toxicity * statistika a číselné údaje   MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• srovnávací studie MeSH