Human health risk assessment of skin patch leachables in artificial sweat


An analytical laboratory working on behalf of a pharmaceuticals manufacturer.


A number of organic chemicals were detected in artificial sweat tests on a skin patch designed to supply an anaesthetic to patients. Some of these were found at levels above the relevant analytical evaluation threshold (AET).

Project goals

Bibra was asked to evaluate the risks posed by the potential leachables found at levels above the AET to the health of patients exposed dermally for six 30-day periods in a lifetime.


The organic compounds were evaluated on the worst-case assumption that the highest levels detected in the artificial sweat tests might be the same as those experienced by patients during actual use. The publicly-available literature was searched for data (using appropriate names, CAS RNs and synonyms) on these potential leachables, to inform on the risks of both local and systemic toxicity. For the less well-studied compounds, the threshold of toxicological concern (TTC) principal was also utilised. Critical points of departure were identified and compared to calculated exposures, enabling bibra to conclude on risk.

Project outcome

There were no concerns for local toxicity for any of the evaluated chemicals. Regarding systemic effects, the possibility of allergic skin reactions could not be entirely ruled out for a single potential leachable; health risks from the remaining chemicals are expected to be negligible.

Bibra project team

Beth O’Connell
James Hopkins


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