Evaluation of sevoflurane volatilization from gel and microsphere formulations and prediction of workplace exposure

The general inhalation anesthetic sevoflurane can be used as a topical analgesic in patients with painful wounds. For this new indication, it is irrigated in its liquid formulation into the wound bed, which inevitably causes room pollution. This investigation aimed to analyze the environmental contamination caused by new sevoflurane gel and microsphere formulations at different concentrations (50 %, 30 %, and 10 %) to find which would produce air levels below 2 ppm. The weight loss over time of each formulation was recorded to calculate the amount of sevoflurane volatilized, and the associated room pollution was further calculated under demanding conditions (a small 12 m³ room with three air exchanges per hour, a patient treated every 30 min). Air levels below 2 ppm were found for the gel at 10 % and the microspheres at 30 %. Both new formulations would reduce the environmental pollution caused by unformulated sevoflurane, further improving occupational safety when treating painful wounds.