Standard to Meet
| Compound Assessment
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Human Toxicity
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Compound causes one or more of the following:- cholestasis
- steatosis
- phospholipidosis
- fibrosis
- cell death
in humans; or exemplifies an in vitro mechanism underlying one of these toxicities.
| Amiodarone causes abnormal liver function test results in 15-50% of patients. The spectrum of liver injury is wide, ranging from isolated asymptomatic transaminase elevations to a fulminant disorder. Hepatotoxicity is usually predictable, dose dependent, and has a direct hepatotoxic effect. Clinically important liver disease develops in less than 5% of patients.
The pseudoalcoholic liver injury can range from steatosis, to alcoholic hepatitis-like neutrophilic infiltration and Mallory's hyaline, to cirrhosis. Rarely, an acute idiosyncratic hepatocellular injury resembling viral hepatitis or cholestatic hepatitis occurs. Hepatic granulomas have occasionally been observed.
Features that represent a direct effect of the drug on the liver and that are common to the majority of long-term recipients are ultrastructural phospholipidosis, unaccompanied by clinical liver disease. The cationic amphiphilic drug and its major metabolite desethylamiodarone accumulate in hepatocyte lysosomes and mitochondria and in bile duct epithelium.
Amiodarone has been shown to induce steatosis in both animal models and humans. Steatosis is a common, early histological finding of hepatic injury and is characterized by micro- and/or macrovesicular hepatocellular lipid accumulation. Although steatosis is reversible, it can lead to steatohepatitis involving hepatocellular necrosis and/or apoptosis.
Amiodarone’s toxicity seems to be generic with respect to cell type; and the limiting toxicity in humans is normally pulmonary, with adverse events observed in 5% of patients. Asymptomatic "foamy cell" phospholipidosis is common, but acute and chronic life-threatening epithelial cell apoptosis with fibrosis and inflammatory responses are observed with significant frequency.
References:
- | Medscape Drug-Induced Hepatotoxicity Specific Agents and Their Effects on the Liver |
- | Harrison's Principles of Internal Medicine, 17e, Chapter 299. Toxic and Drug-Induced Hepatitis |
- | Spyros A. Papiris, Christina Triantafillidou, Likurgos Kolilekas, Despoina Markoulaki, and Effrosyni D. Manali, "Amiodarone: Review of Pulmonary Effects and Toxicity", Drug Saf 2010; 33 (7): 539-558. |
- | Additional references under Biochemical mechanism of toxicity. |
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Toxicity occurs via one or more of the following mechanisms:- mitochondrial disruption
- inhibition of lipid transport or metabolism
- nuclear receptor modulation
- complexation of phospholipids
| As a cationic ampiphilic compound, amiodarone causes phospholipidosis, with accumulation of lamellar bodies in lipid-rich organs such as lung and liver.
Amiodarone shows typical toxicity associated with redox cycling agents: inhibition of electron transport in oxidative phosphorylation plus inhibition of fatty acid β-oxidation, which causes steatosis. The effect on mitochondrial membrane potential is biphasic, with increased potential at low dose and decreased potential at high dose, implying multiple points of interaction.
References:
- | M. Teresa Donato, Alicia Martínez-Romero, Nuria Jiménez, Alejandro Negro, Guadalupe Herrer, José V. Castell, José-Enrique O’Connor, M. José Gómez-Lechón, "Cytometric analysis for drug-induced steatosis in HepG2 cells.", Chemico-Biological Interactions 181 (2009) 417–423. |
- | Spyros A. Papiris, Christina Triantafillidou, Likurgos Kolilekas, Despoina Markoulaki, and Effrosyni D. Manali, "Amiodarone: Review of Pulmonary Effects and Toxicity", Drug Saf 2010; 33 (7): 539-558. |
- | I. Grattagliano et al. Biochemical mechanisms in drug-induced liver injury: Certainties and doubts World J Gastroenterol. 2009 October 21; 15(39): 4865–4876. |
- | Spaniol M. et al. Toxicity of amiodarone and amiodarone analogues on isolated rat liver mitochondria. J Hepatol. 2001 Nov; 35(5):628-36. |
- | Fromenty B. et al. Dual effect of amiodarone on mitochondrial respiration. Initial protonophoric uncoupling effect followed by inhibition of the respiratory chain at the levels of complex I and complex II. (1990) J Pharmacol Exp Ther 255:1377–1384. |
- | Fromenty B et al. Amiodarone inhibits the mitochondrial b-oxidation of fatty acids and produces microvesicular steatosis of the liver in mice. (1990) J Pharmacol Exp Ther 255:1371–1376. |
- | Fromenty B. et al. Inhibition of mitochondrial beta-oxidation as a mechanism of hepatotoxicity. (1995) Pharmacol Ther 67:101–154. |
- | K.M. Waldhauser et al. Hepatocellular Toxicity and Pharmacological Effect of Amiodarone and Amiodarone Derivatives The Journal of Pharmacology and Experimental Therapeutics 2006 Vol. 319, No. 3. |
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Therapeutic target.
| The antiarrhythmic effect of Amiodarone is due to at least two major properties: a prolongation of the myocardial cell action potential duration and refractory period (potassium channel inhibition) and noncompetitive α- and β-adrenergic inhibition.
References:
- | Drugs.com: Amiodarone |
- | K.M. Waldhauser et al. Hepatocellular Toxicity and Pharmacological Effect of Amiodarone and Amiodarone Derivatives The Journal of Pharmacology and Experimental Therapeutics 2006 Vol. 319, No. 3. |
- | Singh BN (1996) Antiarrhythmic actions of amiodarone: a profile of a paradoxical agent. Am J Cardiol 78:41–53. |
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Biochemical mechanism of toxicity.
| Amiodarone accumulates within mitochondria and causes toxicity by uncoupling of oxidative phosphorylation and inhibition of complexes I, II and III and β-oxidation. Inhibition of β-oxidation of fatty acid induces lipid accumulation in liver. Nonspecific hydrophobic interactions with either mitochondrial membrane phospholipids and/or membrane-associated proteins have also been suggested as a mechanism by which amiodarone disrupts mitochondrial function.
References:
- | I.Grattagliano et al. Biochemical mechanisms in drug-induced liver injury: Certainties and doubts World J Gastroenterol. 2009 October 21; 15(39): 4865–4876. |
- | Spaniol M. et al. Toxicity of amiodarone and amiodarone analogues on isolated rat liver mitochondria. J Hepatol. 2001 Nov; 35(5):628-36. |
- | Fromenty B. et al. Dual effect of amiodarone on mitochondrial respiration. Initial protonophoric uncoupling effect followed by inhibition of the respiratory chain at the levels of complex I and complex II. (1990) J Pharmacol Exp Ther 255:1377–1384. |
- | Fromenty B et al. Amiodarone inhibits the mitochondrial b-oxidation of fatty acids and produces microvesicular steatosis of the liver in mice. (1990) J Pharmacol Exp Ther 255:1371–1376. |
- | Fromenty B. et al. Inhibition of mitochondrial beta-oxidation as a mechanism of hepatotoxicity. (1995) Pharmacol Ther 67:101–154. |
- | K.M. Waldhauser et al. Hepatocellular Toxicity and Pharmacological Effect of Amiodarone and Amiodarone Derivatives The Journal of Pharmacology and Experimental Therapeutics 2006 Vol. 319, No. 3. |
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PK-ADME
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PK parameters 1:
- recommended dose
- Cmax
- Vd
- half-life
| Maximum plasma concentrations are attained 3 to 7 hours after a single dose.
Plasma concentrations with chronic dosing at 100 to 600 mg/day are approximately dose proportional, with a mean 0.5 mg/L increase for each 100 mg/day.
Amiodarone has a very large but variable volume of distribution, averaging about 60 L/kg, because of extensive accumulation in various sites, especially adipose tissue and highly perfused organs, such as the liver, lung, and spleen.
Following single dose administration in 12 healthy subjects, amiodarone exhibited multi-compartmental pharmacokinetics with a mean apparent plasma terminal elimination half-life of 58 days (range 15 to 142 days) for amiodarone and 36 days (range 14 to 75 days) for the active metabolite DEA.
References:
- | WikiDoc: Amiodarone Pharmacokinetics and Molecular Data |
- | Vijaya Jaiswal et al. | Comparative bioavailability study with two amiodarone tablet formulations in healthy subjects, Int. J. Res. Pharm. Sci. Vol-1, Issue-4, 481-485, 2010. |
- | Riva E. et al Pharmacokinetics of amiodarone in man. J Cardiovasc Pharmacol. 1982 Mar-Apr;4(2):264-9. |
- | Xu Meng et al. Bioavailability of amiodarone tablets administered with and without food in healthy subjects The American Journal of Cardiology Volume 87, Issue 4, 15 February 2001, Pages 432-435. |
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Therapeutic window.1
| Therapeutic range 1.0 - 2.5 mg/L.
Arrhythmias recurred in 47% of patients with serum amiodarone concentrations of less than 1.0 mg/L, The risk of developing adverse reactions was related to serum amiodarone concentrations. Adverse reactions were common in patients with serum values exceeding 2.5 mg/L,
References:
- | Rotmensch HH, et al. Steady-state serum amiodarone concentrations: relationships with antiarrhythmic efficacy and toxicity. Ann Intern Med. 1984 Oct; 101(4):462-9. |
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Metabolically activated (optional), active metabolite known and available for testing.2
| Amiodarone is extensively metabolized in the liver via CYP2C8. The major metabolite of amiodarone is desethylamiodarone (DEA), which also has antiarrhythmic properties.
No therapeutic range is established for DEA; activity and serum concentration are similar to parent drug.
References:
- | Katri Maria Waldhauser, Michael Torok, Huy-Riem Ha, Urs Thomet, Daniel Konrad, Karin Brecht, Ferenc Follath, and Stephan Krahenbuhl, "Hepatocellular Toxicity and Pharmacological Effect of Amiodarone and Amiodarone Derivatives", JPET 319:1413–1423, 2006. |
- | Medscape: [http://www.medscape.com/viewarticle/730896_3 Pharmacokinetics and Metabolism
N-Desethylamiodarone (hydrochloride)] Cayman Chemical Item Number 9000537 Purity > 95% 10mg = 88$ |
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Omics and IC50 Data
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Gene expression profiles known.3
| HepaRG cells: Induction of Vesicular Steatosis by Amiodarone and Tetracycline Is Associated with Up-regulation of Lipogenic Genes in HepaRG Cells S. Antherieu et al. Hepatology 2011;53:1895-1905
Mice Disruption of Hepatic Lipid Homeostasis in Mice after Amiodarone Treatment Is Associated with Peroxisome Proliferator-Activated Receptor-alpha Target Gene Activation Tanya C. et al. The Journal of Pharmacology and Experimental Therapeutics Vol. 311, No. 3
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Proteomics profiles known.3
| HepaG2: Anke Van Summeren et al. Proteomics Investigations of Drug-Induced Hepatotoxicity in HepG2 Cells Toxicol. Sci. (2011) 120 (1): 109-122.
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Metabonomics profiles known.3
| Huy Riem Ha et al. Identification and quantitation of novel metabolites of amiodarone in plasma of treated patients European Journal of Pharmaceutical Sciences Volume 24, Issue 4, March 2005, Pages 271-279
Mina Hasegawa et al. Urinary metabolic fingerprinting for amiodarone-induced phospholipidosis in rats using FT-ICR MS, Experimental and Toxicologic Pathology Volume 59, Issue 2, 17 October 2007, Pages 115-120
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Fluxomics profiles known.3
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Epigenomics profiles known.3
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Observed IC50 for in vitro cellular efficacy.4
| Amiodarone is a sodium channel blocker. Amiodarone inhibited [3H]BTXB binding in a dose-dependent fashion, with an estimated IC50 value of 3.6 microM. This IC50 value is similar to reported clinically effective serum concentrations of amiodarone RS Sheldon et al. Amiodarone: biochemical evidence for binding to a receptor for class I drugs associated with the rat cardiac sodium channel, Circulation Research. 1989;65:477-482 > Amiodarone inhibited the activated muscarinic acetylcholine receptor-operated K+ current (role in the repolarization of atrial action potential) with IC50 values around 2 microM (Y Watanabe et al.). Inhibitory effect of amiodarone on the muscarinic acetylcholine receptor-operated potassium current in guinea pig atrial cells PET November 1996 vol. 279 no. 2 617-624.
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Observed IC50 for in vitro cellular toxicity studies. 4
| HepG2 cells:
12 uM MEC – increased mitochondrial membrane potential
25 uM MEC – lipid accumulation
35 uM MEC – ROS accumulation
200 uM MEC – decreased mitochondrial membrane potential and GSH levels
75 - 105 uM IC50 - cell death
hESC-derived cardiomyocytes:
0.5 uM IC50 – cell death
Bovine pulmonary artery endothelial cells:
2 uM MEC - phoshpolipid accumulation (at 4 hours)
20 uM IC50 - cell death
References:
- | W. J. MARTIN II, and D. M. HOWARD, "In Vitro Evidence for the Direct Toxicity of the Drug", Am J Pathol 1985, 120:344-350. |
- | Elizabeth Roquemore, Rahman Ismail, Sharon Davies, Catherine Hather, Elizabeth Price, Alexander Harrison, P J Kemp, N D Allen, and Stephen Minger (2011). Poster Download. |
- | Golli-Bennour EE et al. Cytotoxicity effects of amiodarone on cultured cells. Exp Toxicol Patho (2010), doi:10.1016/j.etp.2010.10.008
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- | M. Teresa Donato, Alicia Martínez-Romero, Nuria Jiménez, Alejandro Negro, Guadalupe Herrer, José V. Castell, José-Enrique O’Connor, M. José Gómez-Lechón, "Cytometric analysis for drug-induced steatosis in HepG2 cells.", Chemico-Biological Interactions 181 (2009) 417–423. |
- | Jinghai J. Xu, Peter V. Henstock, Margaret C. Dunn, Arthur R. Smith, Jeffrey R. Chabot, and David de Graaf, "Cellular Imaging Predictions of Clinical Drug-Induced Liver In",TOXICOLOGICAL SCIENCES 105(1), 97–105 (2008). |
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Physical Properties
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Accepted and listed within the ToxCast/Tox21 program.5
| Yes - Included in ToxCast Phase I and II Chemicals List.
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Defined and confirmed structure and isomeric form(s).
| Structure uploaded on the wiki.
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Substance stability.
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Soluble in buffer solution at 30 times the in vitro IC50 for toxicity.6
| Amiodarone water solubility: 0.07164 g/100ml (25°C) at pH 6.5, solubility was not substantially affected at pH range of 1.5-7.5 in aqueous solutions. (Bonati M, Gaspari F, D'Aranno V, Benfenati E, Neyroz P, Galletti F, Tognoni G. Physicochemical and analytical characteristics of amiodarone.J Pharm Sci. 1984; 73(6):829-31).
Amiodarone estimated intrinsic solubility : 1.5085E-05 mg/ml
Amiodarone estimated solubility in pure water at pH 7.5: 1.071E-03 mg/ml
Amiodarone estimated solubility in water at pH 7.4: 1.33E-03 mg/ml
(Calculations performed using ACD/PhysChem v 9.14)
Solubility as a function of pH and other parameters available on the wiki.
Amiodarone hydrochloride 50 mg/ml Sigma Aldrich A8423 Technical specification.
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Solubility in DMSO 100 times buffer solubility.
| Amiodarone hydrochloride soluble to 50 mM in DMSO Tocris Bioscience
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Vessel binding properties.7
| Sorption of amiodarone to flexible PVC containers. [Weir SJ, Myers VA, Bengtson KD, Ueda CT. Sorption of amiodarone to polyvinyl chloride infusion bags and administration sets. Am J Hosp Pharm 1985; 42(12):2679-83].
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Commercial availability at > 95% (> 99% is preferred).
| Sigma Aldrich (A8423) 1g/61.60€ purity >98% Sigma Aldrich A8423 Product details
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Vapor pressure. (Non-volatile)
| Estimated vapor pressure: 6.56E-05 mmHg (Calculation performed using EPI Suite v4.10)
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Criteria Notes
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1. | The in vivo therapeutic window is used to estimate an appropriate concentration for in vitro toxicity assays. This in vitro concentration should also be consistent with the exposure implied by pharmacokinetics parameters. |
2. | We prefer compounds that require metabolic activation, although standards that are active in themselves will be accepted if they have otherwise valuable properties. We require knowing the active metabolite, and we prefer compounds where the metabolite is stable and can be independently tested in order to verify the mechanism of toxicity as well as of metabolic activation in the test cell line. |
3. | Literature data for at least one, but not necessarily all, of the ‘omics datasets is desired. This requirement can be waived in special cases. |
4. | The IC50’s for in vitro efficacy and toxicity should be consistent with the therapeutic ratio observed in the clinic. These parameters will be dependent on specific cell type and culture conditions, but differences of more than 30-fold in the in vitro vs. in vivo therapeutic ratios should be considered suspect and carefully justified. |
5. | This is not a requirement, but compounds utilized in the EPA testing program can be assumed to have physical properties verified to be suitable for in vitro cellular assays. |
6. | Sparing soluble compounds may be assayed for solubility in serum and the percent serum used specified here. |
7. | This property will be measured when a sample of compound becomes available. |
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