Caffeine

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a dermal sensitization study (RCC, 2005) with anhydrous caffeine (purity >= 99.5% in ethanol:water, 70:30 % (w/v), young adult CBA mice (4 females/group) were tested using the method of the Local Lymph Node Assay. Three groups of mice were applied caffeine at concentrations of 0.5, 2, or 5% (w/v) to the dorsal surface of each ear lobe (ca. 50 mm² for each ear) for 3 consecutive days; the control group was applied the vehicle in the same manner. Five days after the first application, all mice were injected i.v. with ³H-methyl thymidine (³HTdR) and were sacrificed 5 hours later. The draining auricular lymph nodes were excised and pooled per group. Single cell suspensions of pooled lymph nodes were prepared; and ³HTdR incorporation was measured by beta-scintillation counting. A separate positive control study with alpha-hexylcinnamate (5, 10, 25 % (w/v) in acetone:olive oil, 4:1 (v/v) was carried out routinely. The study was conducted in accordance with OECD TG 429 and with GLP guidelines.

No deaths, no clinical symptoms and no adverse effects on body weight were observed. Stimulation index (SI) was 0.91, 0.92, and 0.87 for the groups treated with caffeine at 0.5, 2, and 5%, respectively. An EC3 value was not calculated, since all SI’s were below 3. The positive control study gave the expected results.

In this study, anhydrous caffeine is not a dermal sensitizer.

Migrated from Short description of key information:
Caffeine was not sensitizing in a mouse Local Lymph Node Assay.

Justification for classification or non-classification

There is no need to classify caffeine for sensitization according to GSH criteria or Directive 67/548/EC.