The International EU/COLIPA In Vitro Phototoxicity Validation Study: Results of Phase II (Blind Trial). Part 1: The 3T3 NRU Phototoxicity Test

Spielmann, Horst; Balls, Michael; Dupuis, J.; Pape, Wolfgang; Pechovitch, Georges; Silva, O. de; Holzhütter, Hermann−Georg; Clothier, Richard H.; Desolle, P.; Gerberick, Frank; Liebsch, Manfred; Lovell, W.W.; Maurer, Tobias; Pfannenbecker, U.; Potthast, Jörg; Csató, M.; Śladowski, Dariusz; Steiling, W.; Brantom, Paul

doi:10.1016/s0887-2333(98)00006-x

Cited by 261 publications

(168 citation statements)

References 9 publications

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“…When both photochemical and PK data are taken into account, FA was more likely to be phototoxic than the others; the photosafety of FA was then examined by both 3T3 NRU PT, a well validated alternative method for photosafety assessment (Spielmann et al, 1998), and the rat in vivo phototoxicity test. FF was also tested for comparison.…”

Section: Resultsmentioning

confidence: 99%

New Photosafety Assessment Strategy Based on the Photochemical and Pharmacokinetic Properties of Both Parent Chemicals and Metabolites

et al. 2015

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Photoreactivity and dermal/ocular deposition of compounds have been recognized as key considerations for evaluating the phototoxic risk of compounds. Because some drugs are known to cause phototoxic reactions via generation of potent phototoxic metabolites, photosafety assessments on parent drugs alone may lead to false predictions about their photosafety. This study aimed to establish a new photosafety assessment strategy for evaluating the in vivo phototoxic potential of both a parent substance and its metabolites. The in vivo phototoxic risk of fenofibrate (FF) and its metabolites, fenofibric acid (FA) and reduced fenofibric acid, were evaluated based on photochemical and pharmacokinetic analyses. FF and FA exhibited intensive UV absorption, with molar extinction coefficient values of 17,000 (290 nm) and 14,000 M 21 cm 21 (295 nm), respectively. Superoxide generation from FA was significantly higher than from FF, and a marked increase in superoxide generation from FF was observed after incubation with rat hepatic S9 fractions, suggesting enhanced photoreactivity of FF after metabolism. FA showed high dermal/ocular deposition after oral administration (5 mg/kg, p.o.) although the concentration of FF was negligible, suggesting high exposure risk from FA. On the basis of these findings, FA was deduced to be a major contributor to phototoxicity induced by FF taken orally, and this prediction was in accordance with the results from in vitro/in vivo phototoxicity tests. Results from this study suggest that this new screening strategy for parent substances and their metabolites provides reliable photosafety information on drug candidates and would be useful for drug development with wide safety margins.

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Section: Resultsmentioning

confidence: 99%

New Photosafety Assessment Strategy Based on the Photochemical and Pharmacokinetic Properties of Both Parent Chemicals and Metabolites

et al. 2015

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“…For DMSO and other organic solvents, a final concentration of approximately 1% v/v (but no more than 10% v/v) is recommended for administration to cells (Spielmann et al, 1998a) to avoid solvent-induced toxicity. Therefore, with a poorly water-soluble substance, improved dissolution could be obtained using 10% v/v DMSO, and in the case of 2-octyl salicylate, it therefore became possible to correctly evaluate false positive results.…”

Section: Discussionmentioning

confidence: 99%

“…Table 2 shows the results of reproducibility testing of the eight substances with logKow values > 4. Tests were repeated in triplicate for both the conventional and mod- Spielmann et al (1995Spielmann et al ( , 1998a Spielmann et al (1995Spielmann et al ( and 1998aSpielmann et al ( , 1998b Spielmann et al (1998aSpielmann et al ( , 1998b Spielmann et al (1998aSpielmann et al ( , 1998b Spielmann et al (1998aSpielmann et al ( , 1998b 28 UV Absorbers p-Aminobenzoic Acid In such cases, a formal "PIF=1*" is used to characterize the result.…”

Section: Evaluation Of 30 Substances Using the Conventional And Modifmentioning

confidence: 99%

Development of a modified 3T3 Neutral Red Uptake Phototoxicity Test protocol for evaluation of poorly water-soluble substances

et al. 2017

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-The 3T3 neutral red uptake phototoxicity test (OECD TG432) is an alternative phototoxicity test method that is relatively easy and rapid to implement, with results obtainable in a short time, and is reported to have high reproducibility compared with in vivo assay methods. However, this method has been shown to be unsuitable for testing poorly water-soluble substances, which tend to separate out when mixed with the assay buffer solution. This causes difficulties in determining the dose dependency of substances and subsequent determination of the photoirritation factor because the ratio of cell viability, expressed as the half-maximal inhibitory concentration (IC 50 ) in the presence or absence of light, is not calculable. In this study, we investigated the optimum conditions for the evaluation of poorly water-soluble substances. In the conventional method, the final solvent concentration was 1% and the pre-incubation time was 60 min, but in the modified method, 10% and 5 min were used, respectively. Next, the results from the conventional method were compared with those of our modified method, which was found to be viable and comparable with the conventional method. Moreover, the false positive results frequently obtained with poorly water-soluble substances in the conventional method were not evident with the modified method, thus confirming its usefulness for the evaluation of such substances. We therefore propose that the modified method can be used for the in vitro testing of poorly water-soluble substances in phototoxicity evaluations.

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“…A representative set of test chemicals covering all major classes of phototoxins was selected according to results from standardised photopatch testing in humans (21). The results obtained in this in vitro test under blind conditions were reproducible, and the correlation between in vitro and in vivo data was almost perfect (20). Therefore, the ECVAM Scientific Advisory Committee (ESAC) concluded in 1998, that the 3T3 NRU PT is a scientifically validated test which is ready to be considered for regulatory acceptance (8).…”

Section: Regulatory Acceptance Of the Successfully Validated 3t3 Nru mentioning

confidence: 99%

Validation and Regulatory Acceptance of New Carcinogenicity Tests

Spielmann

2003

Toxicol Pathol

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The 3 Rs concept, which was developed by Russell and Burch in 1959, was implemented into the legal framework in the European Union (EU) for the protection of vertebrate animals used for experimental and other scientific purposes, when Directive 86/609/EEC was adopted in 1986. To reduce or replace animal testing for regulatory purposes, nonanimal tests must be independently validated to prove that they can provide information that is relevant and reliable for hazard prediction in vivo. At the end of the 1980s, no scientific concept existed for the formal validation of in vitro toxicity tests, so a small group of European and American scientists developed a set of principles for experimental validation, which was accepted internationally by the OECD in 1996. A major breakthrough was the acceptance in the EU of the scientifically validated in vitro toxicity test for phototoxic potential in 2000, which was accepted by the OECD at the worldwide level in 2002. Taking the progress in the development and validation of alternative toxicity tests during the past decade into account, the current concepts of developing alternatives to the standard 2-year rodent bioassay for carcinogenicity testing are discussed.

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The International EU/COLIPA In Vitro Phototoxicity Validation Study: Results of Phase II (Blind Trial). Part 1: The 3T3 NRU Phototoxicity Test

Cited by 261 publications

References 9 publications

New Photosafety Assessment Strategy Based on the Photochemical and Pharmacokinetic Properties of Both Parent Chemicals and Metabolites

New Photosafety Assessment Strategy Based on the Photochemical and Pharmacokinetic Properties of Both Parent Chemicals and Metabolites

Development of a modified 3T3 Neutral Red Uptake Phototoxicity Test protocol for evaluation of poorly water-soluble substances

Validation and Regulatory Acceptance of New Carcinogenicity Tests

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