Evaluation of decontamination efficacy of four antineoplastics (ifosfamide, 5-fluorouracil, irinotecan, and methotrexate) after deliberate contamination.

The main objective was to determine the decontamination efficacy of quaternary ammonium, 0.1% sodium hypochlorite, and water after deliberate contamination with four antineoplastics (ifosfamide, 5-fluorouracil, irinotecan, methotrexate). A stainless-steel surface was deliberately contaminated with ifosfamide (15 µg), 5-fluorouracil (10 µg), irinotecan (1 µg), and methotrexate (1 µg). First, a single decontamination step with either water, quaternary ammonium, or 0.1% sodium hypochlorite was tested. Then, the effect of up to four successive decontamination steps with either quaternary ammonium or 0.1% sodium hypochlorite was tested. Commercial wipes consisting of two layers of non-woven microfibers with an inner layer of highly absorbent viscose fibers were used. Triplicate surface samples were obtained and tested by ultra-performance liquid chromatography tandem mass spectrometry. The limits of detection were 0.004 ng/cm for ifosfamide, 0.040 ng/cm for 5-fluorouracil, 0.003 ng/cm for irinotecan, and 0.002 ng/cm for methotrexate. After a single decontamination step, the 0.1% sodium hypochlorite eliminated 100% of contamination with 5-fluorouracil, irinotecan, and methotrexate and 99.6 ± 0.5% of ifosfamide contamination. Quaternary ammonium and water also removed 100% of the 5-fluorouracil, and 99.5% to 99.9% of the other three antineoplastics. For ifosfamide, irinotecan, and methotrexate, the decontamination efficacy increased with successive decontamination steps with quaternary ammonium. 5-fluorouracil was undetectable after a single decontamination step. Methotrexate was the only drug for which decontamination efficacy was less than 100% after four decontamination steps. 100% decontamination efficacy was achieved from the decontamination step with 0.1% sodium hypochlorite for 5-fluorouracil, irinotecan, and methotrexate. For ifosfamide, 100% efficacy was achieved only after the third decontamination step. It was possible to make all traces of antineoplastic undetectable after deliberate contamination with 5-fluorouracil, irinotecan, and methotrexate with a 0.1% chlorine solution; up to three decontamination steps were needed to make ifosfamide undetectable. Water or quaternary ammonium removed more than 99.5% of deliberate contamination. In several scenarios, it was necessary to repeat the decontamination to eliminate residual traces. More work is needed to identify the optimal decontamination approach for all of the antineoplastic drugs used.