Efficiency of an optimized decontamination procedure for five intravenous antineoplastic drugs in a compounding isolator of a hospital pharmacy: a real-life study

Introduction
Chemical contamination of work surfaces by antineoplastic drugs (ADs) is a major concern in the hospital setting, starting with the step of drugs preparation under containment primary engineering control. To reduce ADs occupational exposure, international guidelines recommend in particular the implementation of a surface chemical decontamination to reduce contamination of work environment surfaces. The aim of the present study was to optimize the surface decontamination procedure currently in place in terms of professional practices and to evaluate its effectiveness in controlling ADs contamination of surfaces inside a compounding isolator.

Material and Methods
Cleaning frequency, order of use of cleaning products, volumes applied, number of compresses and gestures have been optimized and standardized. Two commercial decontamination solutions were used successively: the neutral detergent KlercideTM followed by the Surfanios IP sterile PAE. Four surfaces inside an isolator used to prepare ADs were monitored. We performed 3 sampling campaigns before the optimization of the procedure and 3 after. In total, 108 wipe samples were collected (54 before and 54 after the optimization). They were analyzed using a highly sensitive validated method by ultra-high performance liquid chromatography coupled with tandem mass spectrometry for quantification of 5 ADs (5-fluorouracil (5FU), cyclophosphamide (CP), methotrexate (MTX), etoposide (ETO), paclitaxel (PCX)).

Results
After optimization of the procedure, a global qualitative reduction of the number of molecules per sample was observed: the percentage of samples with 5 ADs was reduced from 63 to 13%. A decrease in the percentage of detection on surface was particularly noticeable for PCX, ETO and MTX (28, 37, 41%, respectively) compared to CP and 5FU (2 and 7%, respectively). An overall reduction of 60% in the total quantity of molecules found on surfaces was measured. The optimized procedure reduced the total quantity (all samples combined, n=54) of PCX, MTX and ETO by a factor of 7.3, 17 and 20.4 respectively. It was less effective for CP and 5FU, which were reduced by a factor of 2.95 and 2.43 respectively. The 90th percentile of total quantities of 5 ADs measured on surfaces decreased from 3.672 ng/cm² to 0.590 ng/cm². Compared with the Dutch proposed threshold, no contamination greater than 10ng/cm² per AD was observed after optimization. The percentage of values below 0.1ng/cm² went from 77% to 93%, all ADs considered.

Conclusion
Despite persistent contamination, the optimized procedure in place proved effective in lowering surfaces contamination inside the isolator for the ADs studied. However, the procedure needs to be tested on a wider range of molecules. In addition, actions must be taken to lower sources of contamination. Finally, regular staff training on this procedure will help maintain this level of efficiency.

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