Urine tropenol ester levels in workers handling tiotropium bromide synthesis: implications for exposure prevention...

Tropenol ester is a highly toxic anticholinergic substance and an intermediate used in industrial production of the bronchodilator tiotropium bromide. The aim of this study was to systematically test workers involved in its production for tropenol ester in urine to identify any exposure pathways and define additional preventive measures. Twelve workers performing tasks involving potential exposure to tropenol ester were repeatedly monitored at the end of each production cycle. Medical exams revealed no symptoms of acute poisoning with tropenol ester, but biological monitoring of urine showed 36 positive findings in 79 samples, with tropenol ester concentrations ranging between the detection limit of 54 pg/mL and 2160 pg/mL. We managed to establish the cause of only one positive finding, which was a hole in a protective glove, whereas the rest most likely occurred due to human error. Because of this, the plant decided to modify the production process by replacing tropenol ester with a safer intermediate. While it is the safest course of action, there where it cannot be taken, biological monitoring can be very helpful in raising awareness about exposure to toxic substances, including the new ones that have not been studied for their adverse potential.