Standard to Meet
| Compound Assessment
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Human Toxicity
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Compound causes cholestasis, lipid-accumulating disorders (steatosis/phopholipidosis) or cell death in humans.
| 1. The effects of cyclosporine A (CyA) treatment on liver morphology, bile flow and biliary secretion of bile acid, cholesterol and phospholipid and some plasma biochemical indicators of liver function were examined. 2. Wistar rats were treated i.p. with 10 or 20 mg of CyA/kg per day for 1, 2, 3 or 4 weeks. 3. Treatment increased bile acid and bilirubin plasma concentration. Bile flow and biliary secretion of bile acid, cholesterol and phospholipid were reduced in CyA-treated animals. 4. All these effects of the drug appeared at 1 week after the start of treatment and were enhanced during prolonged treatment. Cyclosporine A-induced cholestasis was due to a decrease in both the bile acid-dependent and -independent fractions of bile flow. 5. The reduction in cholesterol and phospholipid biliary output may be secondary to the inhibition of the hepatobiliary flux of bile acid; however, perturbations in the removal of lipids from the canalicular membrane as well as intracanalicular interaction between CyA and lipid vesicles/micelles could also be involved.
Ref: Galán AI, Fernández E, Morán D, Muñoz ME, Jiménez R., "Cyclosporine A hepatotoxicity: effect of prolonged treatment with cyclosporine on biliary lipid secretion in the rat.", Clin Exp Pharmacol Physiol. 1995 Apr;22(4):260-5.
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Toxicity is concentration dependent (non-idiosyncratic).[1]
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Therapeutic target.
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Biochemical mechanism of toxicity.
| N-acetylcysteine protects against toxicity in rats.
Kaya H, Koc A, Sogut S, Duru M,Yilmaz HR, Uz E, Durgut R, Journal of Applied Toxicology : JAT [2008, 28(1):15-20]
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PK-ADME
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PK parameters: recommended dose, Cmax, Vd, and half-life.[2]
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Therapeutic window.[3]
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Metabolically activated (optional), active metabolite known and available for testing.[3]
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Omics and IC50 Data
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Gene expression profiles known.[4]
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Proteomics profiles known.[5]
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Metabonomics profiles known.[5]
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Fluxomics profiles known.[5]
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Epigenomics profiles known.[5]
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Observed IC50 for in vitro cellular efficacy.[5]
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Observed IC50 for in vitro cellular toxicity studies.
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Physical Properties
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Accepted and listed within the ToxCast/Tox21 program.[6]
| Not included in phase I and II ToxCast List U.S EPA/ORD/NCCT. ToxCast Phase I and II Chemicals. December 14, 2010.
soluble in DMSO
(−1 < log P < 6, i.e., log of the octanol/water partition coefficient; 97.5% meet this criteria)
Log P experimental 2.92 [Czogalla A. Oral cyclosporine A – The current picture of its liposomal and other delivery systems. Cell Mol Biol Lett 2008; 14: 139-152]
molecular weight range 250–1000 (90% meet this criteria)
CsA 1202.61g/mol does not meet criteria
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Defined and confirmed structure and isomeric form(s).
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Substance stability.
| Store the product dessicated and protected from light at 2-8 °C. Under these conditions the product is stable for 2 years. It should be re-evaluated for suitability in user’s application every two years. Stock solutions in ethanol or DMSO should be stored at −20 °C. Cyclosporin is stable in solution if protected from light, but its concentration may drop due to adsorption to the container walls.
Measuring the concentration of CsA in solution by HPLC was shown to be significantly temperature-dependent, due to interconversion of CsA between two forms.
Sigma C3662 Product Information Sheet.
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Soluble in buffer solution at 30 times the in vitro IC50 for toxicity.[7]
| Water solubility: 27.67 µg/ml (25°C). It is worth emphasizing that this parameter is temperature dependent in an inversely proportional manner: 106.1 μg/ml at 13°C and 9.29 μg/ml at 38.5°C. This phenomenon can be explained by the conformational change of the Dal amino acid residue in position 8. It loses hydration water with increasing temperature, which affects the CsA conformation and consequently its solubility. CsA also lacks ionizable functional groups, so the manipulation of pH does not enhance its solubility.
(Czogalla A. Oral cyclosporine A – The current picture of its liposomal and other delivery systems. Cell Mol Biol Lett 2008; 14: 139-152)
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Solubility in DMSO 100 times buffer solubility.
| 50 mg/mL Sigma C3662 Product details.
>100 mg/g
(Czogalla A. Oral cyclosporine A – The current picture of its liposomal and other delivery systems. Cell Mol Biol Lett 2008; 14: 139-152)
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Vessel binding properties.[8]
| Cyclosporin is stable in solution if protected from light, but its concentration may drop due to adsorption to the container walls. Sigma C3662 Product Information Sheet
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Commercial availability at > 95% (> 99% is preferred).
| Sigma Aldrich (30024) 25mg/69.30 purity >98.5% Sigma 30024 Product details.
Sigma Aldrich (C3662) 5mg/197.20€ purity >95% Sigma C3662 Product details.
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Vapor pressure. (Non-volatile)
| Estimated vapor pressure: 0 mmHg
(NEELY,WB & BLAU,GE (1985) from SRC PhysProp Database)
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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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