In-Vitro Photoxicity Assessment
We work in partnership with our clients to provide a flexible approach
to phototoxicity assessment in concordance
with current regulatory guidelines (EMEA; FDA). Phototoxicity
may be an issue for compounds that absorb UV and/or visible
radiation and are applied topically, or accumulate in the skin following
administration by other routes (eg. systemic route).
Our specialist laboratory services
- Spectral analysis and photostability studies
- Action spectra
and wavelength dependence
- Phototoxicity assessment:
The ‘workhorse’ assay
for in-vitro photoxicity assessment is the neutral
red uptake phototoxicity assay. Spectratox can also
offer supplementary assays including the photo-micronucleus
assay, photo-comet assay and investigation of protein
expression. Compounds can be tested in different
model systems including simple monolayers; 3D co-cultures
and spheroid cultures; skin equivalent models.
- Assessment of DNA reactivity:
This can be an important issue for compounds that
are altered by light (or their photoproducts). Model
systems range from plasmid DNA to the photo-comet
and micronucleus assays. Base modifications and crosslinks are identified
indirectly via enzyme activity and immunofluorescence staining.
Conversely, our approach can be used in the investigation of the efficacy
and ‘dark’ safety of photoactivated therapeutics under development.
in vitro phototoxicity is the ability of a compound to exhibit phototoxic
properties in experimental models - usually human cell cultures.