Chun-Yip Hon
Ryerson University, Canada
Title: The benefits of quantifying the parent product plus its urinary metabolites when conducting occupational exposure assessments to antineoplastic drugs
Biography
Biography: Chun-Yip Hon
Abstract
Urine samples are collected to determine the body burden of healthcare workers exposed to antineoplastic drugs. However, many studies are limited in that only a fraction of the drug is eliminated unchanged. Given this, researchers have suggested that both the parent product and its metabolites should be quantified. The purpose of this study was to compare body burden levels for the parent product alone (cyclophosphamide or CP) with the levels of CP plus its metabolites. Participants were from six healthcare facilities in the Vancouver area. Participants were asked to provide 24-hour urine samples and the output volume was estimated. The urine was analyzed for CP and three of its metabolites, 4-ketocyclophosphamide, carboxyphosphamide, and N-dechloroethylcyclophosphamide by HPLC-MS/MS. The results were reported as mass of contaminant (in ng) per 24 hours. We obtained 201 urine samples. When looking strictly at the parent product, the average concentration of CP was 285 ng/24 hours. Comparatively, the average concentration of CP plus its metabolites was 2,158 ng/24 hours. Our results suggest that analyzing for CP plus its metabolites provides a more accurate reflection of the overall body burden. The average concentration of CP represented about 13% of the concentration of CP plus its metabolites. This is consistent with reports that <20% of the administered dose of CP is eliminated unchanged in the urine. We therefore recommend that future studies, which assess occupational exposure to antineoplastic drug via urine samples, quantify the parent product and its metabolites.