Background Several departments at Aarhus University Hospital use piperacillin/tazobactam elastomeric pumps, prepared by the Hospital Pharmacy, to give a 24 h continuous infusion to patients who require prolonged intravenous antibiotic treatment. The pumps are used both at the department and as home treatment. The Hospital Pharmacy delivers between 150–200 pumps each month to the wards. The manufacturer of piperacillin/tazobactam (’Stragen’) indicates a stability of 48 h at 2–8°C after reconstitution. Increased stability would have several advantages: the wards could have a small stock of pumps for acute patients and weekend treatment, the home patients could receive more pumps at a time and the Hospital Pharmacy could produce pumps in advance.

Purpose The Hospital Pharmacy investigated if piperacillin/tazobactam solutions 12 g/1.5g in NaCl 0.9% in the Infusor pump LV10, are stable up till 7 days at temperatures between 2–8°C followed by 24 h by temperatures below 32°C.

Materials and methods The piperacillin/tazobactam solutions were prepared in the Hospital Pharmacy. The solutions were reconstituted in 240 ml NaCl 0.9% and transferred to the Infusor pump LV10. The concentration was assayed by HPLC. pH and particle content were measured. The microbiological status was examined by Test for Sterility and Container Closure Integrity Test. The quantitative content was measured after 0, 24, 72, 96 and 168 h of storage at 4°C and 24 h at 32°C after storage 168 h at 4°C. Visual inspections were also performed.

Results The content of piperacillin/tazobactam remained stable during 168 h at 2–8°C followed by 24 h below 32°C, protected from direct sunlight. A slight decrease of the pH values was observed during the test period. The results were within the pH specifications. The particles measured were within specifications. No growth of micro-organisms occurred. No precipitation or change of colour was observed.

Conclusions The piperacillin/tazobactam 12 g/1.5 g solutions are stable 8 days in elastomeric infusion pumps under correct storage conditions: 7 days at 2–8°C followed by 24 h below 32°C, protected from direct sunlight. The Hospital Pharmacy now prepares pumps in advance for the wards and prepares up to 7 pumps at a time per patient for home treatment.

No conflict of interest.