Drug-drug cross contamination in the Swisslog fully automated medication handling system

The risk of drug-drug cross contamination in drug dispensing robots in hospital pharmacies causes cumbersome restraints to be put on the production of the robot for example by scheduling high-risk drugs to be dispensed at the end of the day. However, we were unable to find published data on the matter, and therefore performed a worst-case scenario study to assess the magnitude of the problem.

We measured dexamethasone residue left on the suction cup after the production of 100 and 400 dexamethasone tablets, and after 20 paracetamol tablets used as a negative control.

We found that 32.9 µg and 49.5 µg of dexamethasone had been transferred to the suction cup in the two experiments. This is approximately 1 per mille of the dexamethasone content in a 40 mg tablet.

We conclude that uncoated dexamethasone does shed measurable residue in the robot. It remains unknown to what extent this residue contaminates the subsequent production.