Isoflurane – Evaluation of a BAT value
Assessment Values in Biological Material – Translation of the German version from 2023
Britta Brinkmann1Hans Drexler2 (Head of the working group “Assessment Values in Biological Material” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
Andrea Hartwig1 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
MAK Commission3
1 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
2 Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute and Outpatient Clinic of Occupational, Social, and Environmental Medicine, Henkestraße 9–11, 91054 Erlangen, Germany
3 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated isoflurane [26675-46-7] and a maximum concentration at the workplace (MAK value) of 2 ml/m3 has been set for isoflurane. The substance is used as a volatile anaesthetic, and absorption of isoflurane at the workplace is by inhalation. Human studies are not available to derive a quantitative relationship between the internal dose and the critical toxic effects of isoflurane (neurotoxicity and liver toxicity, effects on reproductive organs). Three studies on surgical employees show a linear correlation between the concentration of isoflurane in the air and urine concentration. In correlation to the MAK value of 2 ml/m3, a biological tolerance value (BAT value) of 4 µg isoflurane/l urine was established. Sampling time is at the end of exposure or end of shift. There are no studies in neonatal or juvenile animals at non-anaesthetic concentrations to derive a no observed adverse effect concentration (NOAEC) for developmental neurotoxic effects of isoflurane. Therefore, isoflurane was assigned to Pregnancy Risk Group D. Since the BAT value was derived in correlation to the MAK value, Pregnancy Risk Group D also applies to the BAT value.
