1
|
Sit RK, Kovarik Z, Maček Hrvat N, Žunec S, Green C, Fokin VV, Sharpless KB, Radić Z, Taylor P. Pharmacology, Pharmacokinetics, and Tissue Disposition of Zwitterionic Hydroxyiminoacetamido Alkylamines as Reactivating Antidotes for Organophosphate Exposure. J Pharmacol Exp Ther 2018; 367:363-372. [PMID: 30190337 PMCID: PMC6223194 DOI: 10.1124/jpet.118.249383] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 08/30/2018] [Indexed: 11/22/2022] Open
Abstract
In the development of antidotal therapy for treatment of organophosphate exposure from pesticides used in agriculture and nerve agents insidiously employed in terrorism, the alkylpyridinium aldoximes have received primary attention since their early development by I. B. Wilson in the 1950s. Yet these agents, by virtue of their quaternary structure, are limited in rates of crossing the blood-brain barrier, and they require administration parenterally to achieve full distribution in the body. Oximes lacking cationic charges or presenting a tertiary amine have been considered as alternatives. Herein, we examine the pharmacokinetic properties of a lead ionizable, zwitterionic hydroxyiminoacetamido alkylamine in mice to develop a framework for studying these agents in vivo and generate sufficient data for their consideration as appropriate antidotes for humans. Consequently, in vitro and in vivo efficacies of immediate structural congeners were explored as leads or backups for animal studies. We compared oral and parenteral dosing, and we developed an intramuscular loading and oral maintenance dosing scheme in mice. Steady-state plasma and brain levels of the antidote were achieved with sequential administrations out to 10 hours, with brain levels exceeding plasma levels shortly after administration. Moreover, the zwitterionic oxime showed substantial protection after gavage, whereas the classic methylpyridinium aldoxime (2-pyridinealdoxime methiodide) was without evident protection. Although further studies in other animal species are necessary, ionizing zwitterionic aldoximes present viable alternatives to existing antidotes for prophylaxis and treatment of large numbers of individuals in terrorist-led events with nerve agent organophosphates, such as sarin, and in organophosphate pesticide exposure.
Collapse
Affiliation(s)
- Rakesh K Sit
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Zrinka Kovarik
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Nikolina Maček Hrvat
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Suzana Žunec
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Carol Green
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Valery V Fokin
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - K Barry Sharpless
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Zoran Radić
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| | - Palmer Taylor
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, San Diego, California (R.K.S., V.V.F., K.B.S.); Institute for Medical Research and Occupational Health, Zagreb, Croatia (Z.K., N.M.H., S.Ž.); SRI International, Menlo Park, California (C.G.); and Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California (Z.R., P.T.)
| |
Collapse
|
2
|
Sterner TR, Ruark CD, Covington TR, Yu KO, Gearhart JM. A physiologically based pharmacokinetic model for the oxime TMB-4: simulation of rodent and human data. Arch Toxicol 2013; 87:661-80. [PMID: 23314320 DOI: 10.1007/s00204-012-0987-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 11/21/2012] [Indexed: 11/29/2022]
Abstract
Multiple oximes have been synthesized and evaluated for use as countermeasures against chemical warfare nerve agents. The current U.S. military and civilian oxime countermeasure, 2-[(hydroxyimino)methyl]-1-methylpyridin-1-ium chloride (2-PAM), is under consideration for replacement with a more effective acetylcholinesterase reactivator, 1,1'-methylenebis{4-hydroxyiminomethyl}pyridinium dimethanesulfonate (MMB-4). Kinetic data in the scientific literature for MMB-4 are limited; therefore, a physiologically based pharmacokinetic (PBPK) model was developed for a structurally related oxime, 1,1'-trimethylenebis{4-hydroximinomethyl}pyridinium dibromide. Based on a previous model structure for the organophosphate diisopropylfluorophosphate, the model includes key sites of acetylcholinesterase inhibition (brain and diaphragm), as well as fat, kidney, liver, rapidly perfused tissues and slowly perfused tissues. All tissue compartments are diffusion limited. Model parameters were collected from the literature, predicted using quantitative structure-property relationships or, when necessary, fit to available pharmacokinetic data from the literature. The model was parameterized using rat plasma, tissue and urine time course data from intramuscular administration, as well as human blood and urine data from intravenous and intramuscular administration; sensitivity analyses were performed. The PBPK model successfully simulates rat and human data sets and has been evaluated by predicting intravenous mouse and intramuscular human data not used in the development of the model. Monte Carlo analyses were performed to quantify human population kinetic variability in the human evaluation data set. The model identifies potential pharmacokinetic differences between rodents and humans, indicated by differences in model parameters between species. The PBPK model can be used to optimize the dosing regimen to improve oxime therapeutic efficacy in a human population.
Collapse
Affiliation(s)
- Teresa R Sterner
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Bldg 837, Wright-Patterson AFB, OH 45433-5707, USA.
| | | | | | | | | |
Collapse
|
8
|
Willems JL, Langenberg JP, Verstraete AG, De Loose M, Vanhaesebroeck B, Goethals G, Belpaire FM, Buylaert WA, Vogelaers D, Colardyn F. Plasma concentrations of pralidoxime methylsulphate in organophosphorus poisoned patients. Arch Toxicol 1992; 66:260-6. [PMID: 1514924 DOI: 10.1007/bf02307171] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Using pharmacokinetic data from healthy human volunteers in a bicompartmental pharmacokinetic model, a repeated dose scheme for pralidoxime methylsulphate (Contrathion) was developed producing plasma levels remaining above the assumed "therapeutic concentration" of 4 mg.l-1. Using the same data, it was found that a concentration of 4 mg.l-1 could also be obtained by a loading dose of 4.42 mg.kg-1 followed by a maintenance dose of 2.14 mg.kg-1.h-1. In order to study the pharmacokinetic behaviour of pralidoxime in poisoned patients, this continuous infusion scheme was then applied in nine cases of organophosphorus poisoning (agents: ethyl parathion, ethyl and methyl parathion, dimethoate and bromophos), and the pralidoxime plasma levels were determined. The mean plasma levels obtained in the various patients varied between 2.12 and 9 mg.l-1. Pharmacokinetic data were calculated, giving a total body clearance of 0.57 +/- 0.27 l.kg-1.h-1 (mean +/- SD), an elimination half-life of 3.44 +/- 0.90 h, and a volume of distribution of 2.77 +/- 1.45 l.kg-1.
Collapse
Affiliation(s)
- J L Willems
- Heymans Institute of Pharmacology, University of Ghent Medical School, Belgium
| | | | | | | | | | | | | | | | | | | |
Collapse
|