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Karasova JZ, Kassa J, Hepnarova V, Pejchal J, Junova L, Andrys R, Malinak D, Bzonek P, Kohoutova Z, Musilek K. Toxicity, pharmacokinetics, and effectiveness of the ortho-chlorinated bispyridinium oxime, K870. Food Chem Toxicol 2022; 167:113236. [PMID: 35738326 DOI: 10.1016/j.fct.2022.113236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 05/31/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022]
Abstract
Oxime reactivators are causal antidotes for organophosphate intoxication. Herein, the toxicity, pharmacokinetics, and reactivation effectiveness of o-chlorinated bispyridinium oxime K870 are reported. Oxime K870 was found to have a safe profile at a dose of 30 mg/kg in rats. It exhibited rapid absorption and renal clearance similar to those of other charged oximes after intramuscular administration. Its isoxazole-pyridinium degradation product was identified in vivo. Although it showed some improvement in brain targeting, it was nevertheless rapidly effluxed from the central nervous system. Its reactivation effectiveness was evaluated in rats and mice intoxicated with sarin, tabun, VX, and paraoxon and compared with pralidoxime and asoxime. K870 was found to be less effective in reversing tabun poisoning compared to its parent unchlorinated oxime K203. However, K870 efficiently reactivated blood acetylcholinesterase for all tested organophosphates in rats. In addition, K870 significantly protected against intoxication by all tested organophosphates in mice. For these reasons, oxime K870 seems to have a broader reactivation spectrum against multiple organophosphates. It seems important to properly modulate the oximate forming properties (pKa) to obtain more versatile oxime reactivators.
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Affiliation(s)
- Jana Zdarova Karasova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic; Biomedical Research Center, University Hospital, Hradec Kralove, Czech Republic.
| | - Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Vendula Hepnarova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Jaroslav Pejchal
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Lucie Junova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Rudolf Andrys
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - David Malinak
- Biomedical Research Center, University Hospital, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Petr Bzonek
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Zuzana Kohoutova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Kamil Musilek
- Biomedical Research Center, University Hospital, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic.
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Manek E, Petroianu GA. Brain delivery of antidotes by polymeric nanoparticles. J Appl Toxicol 2020; 41:20-32. [PMID: 32666582 DOI: 10.1002/jat.4029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/07/2020] [Accepted: 06/07/2020] [Indexed: 02/05/2023]
Abstract
Accidental intoxications from environmental pollutants, as well as intentional self- and chemical warfare-related poisonings affect millions of people worldwide each year. While many toxic agents can readily enter the central nervous system (CNS), the blood-brain barrier (BBB) prevents the brain uptake of most pharmaceuticals. Consequently, poisoning antidotes usually cannot reach their site of action in the CNS in therapeutically relevant concentrations, and thus only provide effective protection to the peripheral nervous system. This limitation can be overcome by encapsulating the antidotes in nanoparticles (NP), which can enhance their CNS accumulation without damaging the integrity of the BBB. Among nanocarriers, polymer-based drug delivery systems exhibit remarkable benefits, such as bioavailability, cell uptake and tissue retention. Furthermore, due to their capacity to mask unfavorable physicochemical properties of cargo drugs, polymeric NPs were able to improve BBB transport of various pharmaceuticals. However, while polymer NP-mediated treatment of various pathological brain conditions, such as glioma and Alzheimer's disease were exhaustively studied, the application of polymeric nanocarriers for brain-targeted delivery of antidote molecules has not been adequately examined. To display its therapeutic potential, we review the state of the art of polymer NP-assisted CNS delivery of antidotes for various poisonings, including heavy metal and organophosphorus intoxications.
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Affiliation(s)
- Eniko Manek
- Herbert Wertheim College of Medicine, Florida International University, Miami, Florida
| | - Georg A Petroianu
- College of Medicine & Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
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Kalász H, Szimrók Z, Karvaly G, Adeghate J, Tekes K. Pharmacokinetics of Two Chlorine-Substituted Bis-Pyridinium Mono-Aldoximes with Regenerating Effect on Butyrylcholinesterase. Molecules 2020; 25:molecules25051250. [PMID: 32164301 PMCID: PMC7179459 DOI: 10.3390/molecules25051250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/27/2020] [Accepted: 03/09/2020] [Indexed: 01/23/2023] Open
Abstract
Our aim was to find chlorine-substituted antidotes against organophosphate poisoning and compare their pharmacokinetics to their parent compound, K-203. White male Wistar rats were intramuscularly injected with K-203, K-867 or K-870. Serum, brain, kidneys, liver, lung, eyes, and testes tissues were taken after 5, 15, 30, 60, and 120 min and analyzed using reversed-phase high-performance liquid chromatography. K-203, K-867, or K-870 was present in every tissue that was analyzed, including the serum, the eyes, testes, liver, kidneys, lungs, and the brain. The serum levels of K-867 and K-870 (chlorine-substituted derivatives of K-203) were nearly constant between 15 and 30 min, while their parent compound (K-203) showed peak level at 15 min after the administration of 30 µmol/rat. Neither K-203, nor K-867 or K-870 were toxic at a dose of 100 µmol/200 g in rats. Chlorine-substitution of K-867 and K-870 produced limited absorbance and distribution compared to their parent compound, K203.
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Affiliation(s)
- Huba Kalász
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary; (Z.S.); (J.A.)
- Kalász Teaching and Research Co., Gvadányi utca 44-46, 1144 Budapest, Hungary
- Correspondence:
| | - Zoltán Szimrók
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary; (Z.S.); (J.A.)
| | - Gellért Karvaly
- Department of Laboratory Medicine, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary;
| | - Jennifer Adeghate
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary; (Z.S.); (J.A.)
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Suite 820, Eye & Ear Building, 203 Lothrop Street, Pittsburgh, PA 15213, USA
| | - Kornélia Tekes
- Department of Pharmacodynamics, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary;
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Iqbal A, Malik S, Nurulain SM, Musilek K, Kuca K, Kalasz H, Fatmi MQ. Reactivation potency of two novel oximes (K456 and K733) against paraoxon-inhibited acetyl and butyrylcholinesterase: In silico and in vitro models. Chem Biol Interact 2019; 310:108735. [PMID: 31276662 DOI: 10.1016/j.cbi.2019.108735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 06/10/2019] [Accepted: 07/01/2019] [Indexed: 10/26/2022]
Abstract
Organophosphates (OPs) irreversibly inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The reactivation of these inhibited enzymes is paramount for their normal function. Present study evaluates reactivation potency of two newly developed oximes, K456 and K733, against paraoxon (POX)-inhibited human-RBC-AChE and human-plasma-BChE in comparison to reported reactivator, pralidoxime (2-PAM). In vitro studies showed higher intrinsic toxicities of both oximes than 2-PAM for AChE. No substantial reactivation of hBChE was noted by tested concentration. Contrary to 2-PAM, the in silico study predicted lower binding free energies for both oximes. However, the detailed interaction study revealed inability of oximes to interact with catalytic anionic site of AChE and hBChE in contrast to 2-PAM. Both in vitro and in silico studies conclude that K456 and K733 are unlikely to be used as reactivators of paraoxon-inhibited AChE or BChE.
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Affiliation(s)
- Amna Iqbal
- Department of Biosciences, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad, 45600, Pakistan
| | - Shahrukh Malik
- Department of Biosciences, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad, 45600, Pakistan
| | - Syed M Nurulain
- Department of Biosciences, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad, 45600, Pakistan
| | - Kamil Musilek
- University Hospital Hradec Kralove, Biomedical Research Center, Hradec Kralove, Czech Republic; University of Hradec Kralove, Faculty of Science, Department of Chemistry, Hradec Kralove, Czech Republic
| | - Kamil Kuca
- University of Hradec Kralove, Faculty of Science, Department of Chemistry, Hradec Kralove, Czech Republic
| | | | - M Qaiser Fatmi
- Department of Biosciences, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad, 45600, Pakistan.
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Lorke DE, Nurulain SM, Hasan MY, Kuča K, Petroianu GA. Oximes as pretreatment before acute exposure to paraoxon. J Appl Toxicol 2019; 39:1506-1515. [PMID: 31264735 DOI: 10.1002/jat.3835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 11/11/2022]
Abstract
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.
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Affiliation(s)
- Dietrich E Lorke
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, University Park GL 495 D, Florida International University, Miami, Florida.,College of Medicine and Health Sciences, Department of Anatomy and Cellular Biology, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Syed M Nurulain
- Department of Bio Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Mohamed Y Hasan
- Department of Pharmacology & Therapeutics, College of Medicine and Health Sciences, UAE University, United Arab Emirates
| | - Kamil Kuča
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Georg A Petroianu
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, University Park GL 495 D, Florida International University, Miami, Florida
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Lorke DE, Petroianu GA. The Experimental Oxime K027-A Promising Protector From Organophosphate Pesticide Poisoning. A Review Comparing K027, K048, Pralidoxime, and Obidoxime. Front Neurosci 2019; 13:427. [PMID: 31191210 PMCID: PMC6547910 DOI: 10.3389/fnins.2019.00427] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/15/2019] [Indexed: 11/13/2022] Open
Abstract
Poisoning with organophosphorus compounds (OPCs) is a major problem worldwide. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory. In search of more efficacious broad-spectrum oximes, new bispyridinium (K-) oximes have been synthesized, with K027 being among the most promising. This review summarizes pharmacokinetic characteristics of K027, its toxicity and in vivo efficacy to protect from OPC toxicity and compares this oxime with another experimental bisquaternary asymmetric pyridinium aldoxime (K048) and two established oximes (pralidoxime, obidoxime). After intramuscular (i.m.) injection, K027 reaches maximum plasma concentration within ∼30 min; only ∼2% enter the brain. Its intrinsic cholinesterase inhibitory activity is low, making it relatively non-toxic. In vitro reactivation potency is high for ethyl-paraoxon-, methyl-paraoxon-, dichlorvos-, diisopropylfluorophosphate (DFP)- and tabun-inhibited cholinesterase. When administered in vivo after exposure to the same OPCs, K027 is comparable or more efficacious than pralidoxime and obidoxime. When given as a pretreatment before exposure to ethyl-paraoxon, methyl-paraoxon, DFP, or azinphos-methyl, it is superior to the Food and Drug Administration-approved compound pyridostigmine and comparable to physostigmine, which because of its entry into the brain may cause unwanted behavioral effects. Because of its low toxicity, K027 can be given in high dosages, making it a very efficacious oxime not only for postexposure treatment but also for prophylactic administration, especially when brain penetration is undesirable.
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Affiliation(s)
- Dietrich E Lorke
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States.,Department of Anatomy and Cellular Biology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Georg A Petroianu
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
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Malfatti MA, Enright HA, Be NA, Kuhn EA, Hok S, McNerney MW, Lao V, Nguyen TH, Lightstone FC, Carpenter TS, Bennion BJ, Valdez CA. The biodistribution and pharmacokinetics of the oxime acetylcholinesterase reactivator RS194B in guinea pigs. Chem Biol Interact 2017; 277:159-167. [PMID: 28941624 DOI: 10.1016/j.cbi.2017.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/13/2017] [Accepted: 09/19/2017] [Indexed: 01/09/2023]
Abstract
Organophosphorus-based (OP) nerve agents represent some of the most toxic substances known to mankind. The current standard of care for exposure has changed very little in the past decades, and relies on a combination of atropine to block receptor activity and oxime-type acetylcholinesterase (AChE) reactivators to reverse the OP binding to AChE. Although these oximes can block the effects of nerve agents, their overall efficacy is reduced by their limited capacity to cross the blood-brain barrier (BBB). RS194B, a new oxime developed by Radic et al. (J. Biol. Chem., 2012) has shown promise for enhanced ability to cross the BBB. To fully assess the potential of this compound as an effective treatment for nerve agent poisoning, a comprehensive evaluation of its pharmacokinetic (PK) and biodistribution profiles was performed using both intravenous and intramuscular exposure routes. The ultra-sensitive technique of accelerator mass spectrometry was used to quantify the compound's PK profile, tissue distribution, and brain/plasma ratio at four dose concentrations in guinea pigs. PK analysis revealed a rapid distribution of the oxime with a plasma t1/2 of ∼1 h. Kidney and liver had the highest concentrations per gram of tissue followed by lung, spleen, heart and brain for all dose concentrations tested. The Cmax in the brain ranged between 0.03 and 0.18% of the administered dose, and the brain-to-plasma ratio ranged from 0.04 at the 10 mg/kg dose to 0.18 at the 200 mg/kg dose demonstrating dose dependent differences in brain and plasma concentrations. In vitro studies show that both passive diffusion and active transport contribute little to RS194B traversal of the BBB. These results indicate that biodistribution is widespread, but very low quantities accumulate in the guinea pig brain, indicating this compound may not be suitable as a centrally active reactivator.
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Affiliation(s)
- Michael A Malfatti
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
| | - Heather A Enright
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Nicholas A Be
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Edward A Kuhn
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Saphon Hok
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - M Windy McNerney
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; War Related Illness and Injury Study Center, Veterans Affairs, Palo Alto, CA 94304, USA
| | - Victoria Lao
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Tuan H Nguyen
- Global Security Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Felice C Lightstone
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Timothy S Carpenter
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Brian J Bennion
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Carlos A Valdez
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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Arshad M, Fatmi MQ, Musilek K, Hussain A, Kuca K, Petroianu G, Kalasz H, Nurulain SM. In silico and in vitro evaluation of two novel oximes (K378 and K727) in comparison to K-27 and pralidoxime against paraoxon-ethyl intoxication. Toxicol Mech Methods 2017; 28:62-68. [PMID: 28722512 DOI: 10.1080/15376516.2017.1357777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Organophosphate (OP) poisoning is a major global health issue; while compounds from this group have been used intensively over the last century, an effective antidote is still lacking. Oxime-type acetylcholinesterase (AChE) reactivators are used to reactivate the OP inhibited AChE. Pralidoxime is the only US Food and Drug Administration approved oxime for therapeutic use but its efficacy has been disappointing. Two novel oximes (K378 and K727) were investigated in silico and in vitro and compared with an experimental oxime (kamiloxime; K-27) and pralidoxime. In silico the molecular interactions between AChE and oximes were examined and binding energies were assessed. LogP (predicted log of the octanol/water partition coefficient) was estimated. In vitro the intrinsic ability of the oximes to inhibit AChE (IC50) and their reactivation potency (R50) when used in paraoxon inhibited human RBC-AChE was determined. Molecular docking revealed that K378 and K727 bind to the peripheral site(s) with high binding energies in contrast to the central binding of K-27 and pralidoxime. LogP values indicating that the novel compounds are significantly less hydrophilic than K-27 or pralidoxime. IC50 of K378 and K727 were comparable (0.9 and 1 µM, respectively) but orders of magnitude lower than comparators. R50 values revealed their inability to reactivate paraoxon inhibited AChE. It is concluded that the novel oximes K378 and K727 are unlikely to be clinically useful. The in silico and in vitro studies described allow avoidance of unnecessary in vivo animal work and contribute to the reduction of laboratory animal use.
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Affiliation(s)
- Maria Arshad
- a Department of Biosciences , COMSATS Institute of Information Technology , Islamabad , Pakistan
| | - Muhammad Qaiser Fatmi
- a Department of Biosciences , COMSATS Institute of Information Technology , Islamabad , Pakistan
| | - Kamil Musilek
- b Department of Chemistry , Faculty of Science, University of Hradec Kralove , Hradec Kralove , Czech Republic.,c University Hospital in Hradec Kralove , Hradec Kralove , Czech Republic
| | - Alamdar Hussain
- a Department of Biosciences , COMSATS Institute of Information Technology , Islamabad , Pakistan
| | - Kamil Kuca
- b Department of Chemistry , Faculty of Science, University of Hradec Kralove , Hradec Kralove , Czech Republic.,c University Hospital in Hradec Kralove , Hradec Kralove , Czech Republic
| | - Georg Petroianu
- d Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine , Florida International University , Miami , FL , USA
| | - Huba Kalasz
- e Department of Pharmacology and Pharmacotherapy , Semmelweis University , Budapest , Hungary
| | - Syed Muhammad Nurulain
- a Department of Biosciences , COMSATS Institute of Information Technology , Islamabad , Pakistan
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Voicu V, Rădulescu FŞ, Medvedovici A. Relationships between the antidotal efficacy and structure, PK/PD parameters and bio-relevant molecular descriptors of AChE reactivating oximes: inclusion and integration to biopharmaceutical classification systems. Expert Opin Drug Metab Toxicol 2014; 11:95-109. [DOI: 10.1517/17425255.2015.980813] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Victor Voicu
- 1Romanian Academy, Medical Sciences Section, Calea Victoriei no. 125, Bucharest – 010071, Romania
- 2University of Medicine and Pharmacy “Carol Davila”, Faculty of Medicine, Department of Clinical Pharmacology, Toxicology and Psychopharmacology, Şcoala Floreasca Street no. 8, Bucharest - 011643, Romania
| | - Flavian Ştefan Rădulescu
- 3University of Medicine and Pharmacy “Carol Davila”, Faculty of Pharmacy, Department of Drug Industry and Pharmaceutical Biotechnology, Traian Vuia Street no. 6, Bucharest-020956, Romania
| | - Andrei Medvedovici
- 4University of Bucharest, Faculty of Chemistry, Department of Analytical Chemistry, Panduri Ave., no. 90, Bucharest- 050663, Romania
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10
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Petroianu GA. Oxime treatment for organophosphorus compound exposure: Getting it (into the brain) might not be that good for you, after all. J Appl Biomed 2014. [DOI: 10.1016/j.jab.2014.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Kalász H, Nurulain SM, Veress G, Antus S, Darvas F, Adeghate E, Adem A, Hashemi F, Tekes K. Mini review on blood-brain barrier penetration of pyridinium aldoximes. J Appl Toxicol 2014; 35:116-23. [PMID: 25291712 DOI: 10.1002/jat.3048] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/14/2014] [Accepted: 06/16/2014] [Indexed: 01/27/2023]
Abstract
This paper reviews the blood-brain barrier (BBB) penetration of newly developed pyridinium aldoximes. Pyridinium aldoximes are highly charged hydrophilic compounds used in the treatment of subjects exposed to organophosphonates because they are effective as acetylcholinesterase reactivators. Pyridinium aldoximes have antidotal effects against poisoning with cholinesterase inhibitors, a frequent problem affecting people working with organophosphate-based insecticides and pesticides. Toxic organophosphonate products such as sarin and tabun can be used by terrorists as chemical warfare agents. This poses a severe challenge to all innocent and peace-loving people worldwide. This review gives a brief summary of BBB transporters and description of the current in vitro and in vivo methods for the characterization of BBB penetration of established and novel pyridinium aldoximes. The authors provide a putative mechanism of penetration, outline some future ways of formulation and discuss the possible advantages and disadvantages of increasing BBB penetration.
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Affiliation(s)
- H Kalász
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089, Budapest, Nagyvárad tér 4, Hungary; Department of Pharmacology and Therapeutics, CMHS, United Arab Emirates University, Al Ain, P.O.Box 17666, United Arab Emirates
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Petroianu GA, Athauda G, Darvas F, Kalasz H, Lorke DE. K-OXIME (K-27): PHOSPHYLATION-INDUCED CHANGES IN LOGP. ACTA ACUST UNITED AC 2014. [DOI: 10.31482/mmsl.2014.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Hashemi F, Laufer R, Szegi P, Csomor V, Kalász H, Tekes K. HPLC determination of brain biogenic amines following treatment with bispyridinium aldoxime K203. ACTA ACUST UNITED AC 2014; 101:40-6. [DOI: 10.1556/aphysiol.101.2014.1.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Gunosewoyo H, Tipparaju SK, Pieroni M, Wang Y, Doctor BP, Nambiar MP, Kozikowski AP. Structural analogs of huperzine A improve survival in guinea pigs exposed to soman. Bioorg Med Chem Lett 2012; 23:1544-7. [PMID: 23395652 DOI: 10.1016/j.bmcl.2012.11.083] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 11/15/2012] [Accepted: 11/20/2012] [Indexed: 11/25/2022]
Abstract
Chemical warfare nerve agents such as soman exert their toxic effects through an irreversible inhibition of acetylcholinesterase (AChE) and subsequently glutamatergic function, leading to uncontrolled seizures. The natural alkaloid (-)-huperzine A is a potent inhibitor of AChE and has been demonstrated to exert neuroprotection at an appropriate dose. It is hypothesized that analogs of both (+)- and (-)-huperzine A with an improved ability to interact with NMDA receptors together with reduced AChE inhibition will exhibit more effective neuroprotection against nerve agents. In this manuscript, the tested huperzine A analogs 2 and 3 were demonstrated to improve survival of guinea pigs exposed to soman at either 1.2 or 2×LD(50).
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Affiliation(s)
- Hendra Gunosewoyo
- Department of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S Wood Street, Chicago, IL 60612, USA
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15
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Voicu V, Rădulescu FŞ, Medvedovici A. Toxicological considerations of acetylcholinesterase reactivators. Expert Opin Drug Metab Toxicol 2012; 9:31-50. [DOI: 10.1517/17425255.2013.736489] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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16
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Time-Dependent Changes of Oxime K027 Concentrations in Different Parts of Rat Central Nervous System. Neurotox Res 2012; 23:63-8. [DOI: 10.1007/s12640-012-9329-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/25/2012] [Accepted: 04/26/2012] [Indexed: 12/22/2022]
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17
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A strategy for changing plasma pralidoxime kinetics and, perhaps, effect in organophosphorus insecticide poisoning. Crit Care Med 2011; 39:908-9. [PMID: 21613850 DOI: 10.1097/ccm.0b013e31820a839b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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18
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Partition of bispyridinium oximes (trimedoxime and K074) administered in therapeutic doses into different parts of the rat brain. J Pharm Biomed Anal 2011; 54:1082-7. [DOI: 10.1016/j.jpba.2010.11.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/08/2010] [Accepted: 11/18/2010] [Indexed: 12/23/2022]
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19
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Balbuena P, Li W, Ehrich M. Assessments of tight junction proteins occludin, claudin 5 and scaffold proteins ZO1 and ZO2 in endothelial cells of the rat blood-brain barrier: cellular responses to neurotoxicants malathion and lead acetate. Neurotoxicology 2010; 32:58-67. [PMID: 20970449 DOI: 10.1016/j.neuro.2010.10.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/12/2010] [Accepted: 10/15/2010] [Indexed: 10/18/2022]
Abstract
The blood-brain barrier (BBB) is essential for central nervous system (CNS) normal function. It is formed by endothelial cells with special characteristics, which confer the BBB with low permeability and high transendothelial electrical resistance (TEER). We previously demonstrated that malathion and lead, two neurotoxicants widely present in the environment, decrease TEER and increase permeability in in vitro models of the BBB. In this study we assessed tight junction disruption at the protein and gene expression levels using a rat brain microvascular endothelial cell line (RBE4) exposed to lead acetate at 10(-5)M and 10(-6)M, malathion at 10(-5)M, malaoxon at 10(-6)M, and their combinations. Cells were incubated with treatments for 2h, 4h, 8h, 16h, and 24h periods. Immunoblotting assessments demonstrated that protein levels of tight junction proteins occludin and claudin 5, and scaffold proteins ZO1 and ZO2 were decreased after treatments. Gene expression determinations did not correlate with the decreases in protein, indicating that the effects on these proteins were post-translational.
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Affiliation(s)
- Pergentino Balbuena
- Virginia-Maryland Regional College of Veterinary Medicine, 1 Duck Pond Drive, Virginia Tech, Blacksburg, VA, USA
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20
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Karasova JZ, Stodulka P, Pohanka M, Kuca K. In Vitro Screening of Blood-Brain Barrier Penetration of Monoquaternary Acetylcholinesterase Reactivators. ANAL LETT 2010. [DOI: 10.1080/00032710903502082] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Karasova JZ, Pohanka M, Musilek K, Zemek F, Kuca K. Passive diffusion of acetylcholinesterase oxime reactivators through the blood-brain barrier: influence of molecular structure. Toxicol In Vitro 2010; 24:1838-44. [PMID: 20546883 DOI: 10.1016/j.tiv.2010.05.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/23/2010] [Accepted: 05/17/2010] [Indexed: 12/21/2022]
Abstract
In this in vitro study, high-performance liquid chromatography (HPLC) was used to determinate the penetration of 30 acetylcholinesterase (AChE) reactivators through the blood-brain barrier (BBB). According to our method, monoquaternary AChE reactivators were found to be able to penetrate the BBB. In addition to molecular structure, molecular weight appears to be an important factor for passive transport of oximes through the BBB. For bisquaternary reactivators, the connecting linker plays a key role in the ability to penetrate into the central nervous system (CNS): simple, short linkers tend to facilitate permeation. The location of groups on the pyridine ring also influences passive transport into the brain; the optimum position of the oxime group was found to be position four (para) and substitution of the oxime group on the pyridine ring by carbamoyl or amidoxime group markedly decreased penetration of AChE reactivators into the CNS.
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Affiliation(s)
- Jana Zdarova Karasova
- Department of Toxicology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic.
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22
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Kalász H, Mincsovics E, Ram N, Kuca K. THIN-LAYER CHROMATOGRAPHY OF PYRIDINIUM ALDOXIMES USING DISTINCT TECHNIQUES FOR DEVELOPMENT. J LIQ CHROMATOGR R T 2010. [DOI: 10.1080/10826071003766161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Huba Kalász
- a Department of Pharmacology and Pharmacotherapy, Faculty of Medicine , Semmelweis University , Budapest, Hungary
| | | | - Nazila Ram
- a Department of Pharmacology and Pharmacotherapy, Faculty of Medicine , Semmelweis University , Budapest, Hungary
| | - Kamil Kuca
- c Center of Advanced Studies, Faculty of Military Health Sciences , Hradec Kralove, Czech Republic
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23
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In vitro screening of blood-brain barrier penetration of clinically used acetylcholinesterase reactivators. J Appl Biomed 2010. [DOI: 10.2478/v10136-009-0005-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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24
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Pyridinium aldoxime analysis by HPLC: the method for studies on pharmacokinetics and stability. Anal Bioanal Chem 2010; 397:579-86. [DOI: 10.1007/s00216-010-3635-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/04/2010] [Accepted: 03/04/2010] [Indexed: 11/26/2022]
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25
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Lorke DE, Petroianu GA. Minireview: does in-vitro testing of oximes help predict their in-vivo action after paraoxon exposure? J Appl Toxicol 2009; 29:459-69. [PMID: 19603416 DOI: 10.1002/jat.1457] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
K-oximes have recently been developed in the search for efficacious broad-band reactivators of acetylcholinesterase (AChE) inhibited by organophosphorus compounds (OPC). Before clinical use, their toxicity and efficacy need to be assessed, and there is clear demand for simple in vitro tests that can predict in vivo performance. This article summarizes our in vitro data obtained for conventional and experimental oximes in human and rat blood exposed to the OPC paraoxon and correlates them with our in vivo results. The intrinsic AChE inhibitory activity of oximes, as reflected by their in vitro IC(50), is strongly correlated with their LD(50) (rat): oximes with a high IC(50) (K-27, K-48, pralidoxime and obidoxime) also show a high LD(50) and are thus relatively non-toxic, whereas oximes K-105, K-108 and K-113 have a low IC(50), a low LD(50) and are far more toxic. The IC(50) is also correlated with the in vivo capacity to protect from paraoxon-induced mortality: oximes with a higher IC(50) reduce the relative risk of death more. In contrast, the protective ability as assessed in vitro by the slope of the IC(50) shift (tanalpha), is not correlated with in vivo protection from paraoxon-induced mortality: the best in vivo protectors (K-27 and K-48) show a much lower tanalpha value (around 2) than K-110 and K-113 (tanalpha around 10), which hardly reduce the relative risk of death after paraoxon exposure. The partition coefficient logP of the individual oximes is inversely correlated with their IC(50) and with their LD(50) and is therefore an indicator of toxicity: strongly hydrophilic oximes tend to be less toxic than less hydrophilic ones. These data highlight the good predictive value of in vitro IC(50) testing for in vivo toxicity and the limited practical significance of in vitro assessment of protective potency.
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Affiliation(s)
- D E Lorke
- Department of Anatomy, FMHS, UAE University, Al Ain, UAE
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26
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Raszewski G, Filip R. Correlation of Therapeutic Effect of Obidoxime and Dosing Time in the Acute Intoxication by Chlorfenvinphos in Rats. Basic Clin Pharmacol Toxicol 2009; 105:37-45. [DOI: 10.1111/j.1742-7843.2009.00398.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Sakurada K, Ikegaya H, Ohta H, Fukushima H, Akutsu T, Watanabe K. Effects of oximes on mitochondrial oxidase activity. Toxicol Lett 2009; 189:110-4. [PMID: 19465093 DOI: 10.1016/j.toxlet.2009.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/14/2009] [Accepted: 05/14/2009] [Indexed: 11/16/2022]
Abstract
Oximes, including 2-pyridinealdoxime methiodide (2-PAM), are reactivators of acetylcholinesterase (AChE) inhibited by organophosphate poisoning. Unfortunately, their clinical use has been limited by their toxicity. To investigate the mechanism of this toxicity, the effects of oximes on the enzymes choline oxidase (ChOD) and cytochrome c oxidase (CyCOD) of the respiratory chain in mitochondria were examined. The oximes 2-PAM, obidoxime, and diacetylmonoxime significantly (P<0.01) inhibited ChOD activity, and the extent of inhibition correlated with the ability to reactivate inhibited AChE. When ChOD activity in mitochondrial extracts was tested, 2-PAM inhibited the activity by 75%, obidoxime and diacetylmonoxime did not significantly inhibit it, and 4-[(hydroxy-imino)methyl]-1-decylpyridinium bromide (4-PAD), which has greater toxicity, increased the amount of product generated in the assay to approximately 200% of normal levels. Similarly, 2-PAM inhibited the activity of CyCOD in mitochondrial extracts whereas obidoxime and diacetylmonoxime did not. One explanation for these findings is that, in addition to their inhibition of mitochondrial oxidases, the oximes may produce excessive reactive oxygen species such as H(2)O(2) in the mitochondrial fraction, which may account for some of their toxicity. This is a preliminary report related to the toxicities of oximes that may participate in the inactivation of mitochondrial oxidase enzymes. This hypothesis should be further investigated by in vivo study, including kinetic determination and free radical work.
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Affiliation(s)
- Koichi Sakurada
- National Research Institute of Police Science, 6-3-1, Kashiwanoha, Kashiwa, Chiba 277-0882, Japan.
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28
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Efficacy of eight experimental bispyridinium oximes against paraoxon-induced mortality: comparison with the conventional oximes pralidoxime and obidoxime. Neurotox Res 2009; 16:60-7. [PMID: 19526299 DOI: 10.1007/s12640-009-9048-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 06/25/2008] [Accepted: 06/25/2008] [Indexed: 10/20/2022]
Abstract
Recently, several experimental K-oximes with two functional aldoxime groups have been synthesized that show excellent in vitro efficacy in protecting acetylcholinesterase (AChE) from inhibition by a broad variety of organophosphorus compounds (OPCs). However, oximes themselves are also AChE inhibitors, albeit at higher concentrations, which is a major cause of their toxicity and may be a dose-limiting factor in oxime therapy. To assess the efficacy of the experimental K-oximes in vivo, the extent of oxime-conferred protection from mortality induced by paraoxon was quantified. Rats received paraoxon in a dosage of 1, 5, or 10 mumol, and immediately thereafter intraperitoneal injections of the respective oxime at a dosage of half the LD(01). The relative risk of death (RR) over time was estimated by Cox survival analysis for treatment with experimental K-oximes (K-53, K-74, K-75, K-107, K-108, and K-113), with the clinically available oximes pralidoxime (2-PAM) and obidoxime, and with the well-characterized K-oximes K-27 and K-48, comparing results with the no-treatment group. Best protection was conferred by K-27, reducing the RR to 20% of controls (P </= 0.05), which was significantly (P <or= 0.05) better than all other tested oximes. Marked reduction in mortality was also achieved by K-48 and the three new bispyridinium oximes containing two aldoxime groups, but no xylene linker: K-48 (RR = 0.32), K-53 (RR = 0.36), K-74 (RR = 0.42), K-75 (RR = 0.35). This effect was significantly (P <or= 0.05) superior to that of all other oximes, except K-27. The remaining oximes, i.e., obidoxime (RR = 0.64), 2-PAM (RR = 0.78), K-107 (RR = 0.70), K-108 (RR = 0.77), and K-113 (RR = 0.87) reduced paraoxon-induced mortality only poorly, but significantly (P <or= 0.05). Our data show that K-27, K-48, K-53, K-74, and K-75, due to their far superior in vivo efficacy, are the most promising candidates to eventually replace the established oximes 2-PAM and obidoxime. Further studies in other species exposed to a broader spectrum of OPCs are, however, necessary before considering their use in humans.
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29
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Lorke DE, Nurulain SM, Hasan MY, Kuca K, Musilek K, Petroianu GA. Eight new bispyridinium oximes in comparison with the conventional oximes pralidoxime and obidoxime: in vivo efficacy to protect from diisopropylfluorophosphate toxicity. J Appl Toxicol 2008; 28:920-8. [PMID: 18548743 DOI: 10.1002/jat.1359] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In search for more efficacious reactivators of acetylcholinesterase (AChE) inhibited by organophosphorus compounds, experimental K-oximes have been synthesized which show good in vitro efficacy. However, AChE inhibition by oximes themselves (as quantified by their intrinsic IC50) is the major cause of oxime toxicity and the dose-limiting factor. To assess K-oxime efficacy in vivo, the extent of protection from mortality induced by diisopropylfluorophosphate (DFP) was quantified by Cox survival analysis and compared with that of the clinically available oximes. Oximes were administered in an equitoxic dosage, i.e. half the LD01. Best protection was conferred by K-27, reducing the relative risk of death (RR) to 16% of control RR (P < or = 0.05), which was statistically significantly better (P < or = 0.05) than all other tested oximes, except obidoxime, K-53 and K-75. The efficacy of obidoxime (RR = 0.19), K-48 (RR = 0.28), K-53 (RR = 0.22), K-74 (RR = 0.38) and K-75 (RR = 0.29) was significantly (P < or = 0.05) better than that of 2-PAM (RR = 0.62) and K-113 (RR = 0.73). No significant protective effect was observed for K-107 and K-108. Our LD50 data show that K-107, K-108 and K-113 (which strongly inhibit AChE in vitro) are in vivo markedly more toxic than all other oximes tested and can therefore only be safely administered at a low dosage which is insufficient to protect from DFP-induced mortality. Dosage calculations based on in vitro IC50 measurements may therefore in future replace in vivo LD50 determinations, thereby reducing the number of animals required.
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Affiliation(s)
- D E Lorke
- Department of Anatomy, FMHS, UAE University, Al Ain, United Arab Emirates
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30
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Lorke D, Hasan M, Nurulain S, Shafiullah M, Nagelkerke N, Petroianu G. Effect of intrathecal pralidoxime administration upon survival of rats exposed to the organophosphate paraoxon. Neurotoxicology 2008; 29:663-70. [DOI: 10.1016/j.neuro.2008.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 12/04/2007] [Accepted: 03/14/2008] [Indexed: 11/29/2022]
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