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Updated: Jun 16, 2026
Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
Comparative study of skin phototoxicity with three drugs by an in vivo mouse model
Norihito Matsumoto1, Akira Akimoto, Hiroyuki Kawashima
1Ono Pharmaceutical Co., Ltd., Osaka. no.matsumoto@ono.co.jp
Abstract:
Photosafety evaluation is becoming important during the drug development process in pharmaceutical companies. Both in vitro and in vivo test systems have been developed for the evaluation of phototoxic potential of chemicals. In the present study, we conducted an in vivo phototoxicity test using BALB/c mice. The mice were treated with sparfloxacin, lomefloxacin, or a quinoline derivative orally followed by the irradiation of simulated sunlight, and resulting phototoxic reactions of the ears were assessed. Sparfloxacin and lomefloxacin, but not the quinoline derivative, are well known to cause photoirritation in humans. All three drugs exhibited positive reaction in the 3T3 neutral red uptake phototoxicity test (3T3 NRU PT). In the in vivo test, sparfloxacin and lomefloxacin exhibited positive skin reaction in mice, but the quinoline derivative did not. The results of in vivo phototoxicity test in the mice coincided with phototoxic potential of these drugs in humans. The exposure levels of sparfloxacin or lomefloxacin at the minimum effective dose that exhibited phototoxic reaction in the mice were comparable with those in humans treated with the recommended therapeutic dose.
Insights
This study evaluated drug-induced photosafety using an in vivo mouse model. Results showed the mouse model accurately predicts human phototoxicity for drugs like sparfloxacin and lomefloxacin.
Area of Science:
- Pharmacology
- Toxicology
- Dermatology
Background:
- Photosafety evaluation is crucial in pharmaceutical drug development.
- In vitro and in vivo methods exist for assessing chemical phototoxic potential.
Purpose of the Study:
- To establish an in vivo phototoxicity test using BALB/c mice.
- To compare the phototoxic potential of sparfloxacin, lomefloxacin, and a quinoline derivative in mice and humans.
Main Methods:
- BALB/c mice were orally administered sparfloxacin, lomefloxacin, or a quinoline derivative.
- Mice were exposed to simulated sunlight, and ear phototoxic reactions were assessed.
- Results were compared with the 3T3 neutral red uptake phototoxicity test (3T3 NRU PT) and known human phototoxicity.
Main Results:
- Sparfloxacin and lomefloxacin, known human photosensitizers, showed positive skin reactions in mice.
- The quinoline derivative, not known for human photosensitivity, did not elicit a reaction in mice.
- In vivo mouse results correlated with human phototoxic potential and 3T3 NRU PT findings.
Conclusions:
- The in vivo mouse phototoxicity test effectively predicts human drug photosensitivity.
- Drug exposure levels in mice at the minimum effective phototoxic dose were comparable to human therapeutic doses.
