Background The implementation of dose-banding in centralised cytotoxic preparation units allows the preparation of standardised doses in series. Based on this concept, dose-banded ready-to-administer ganciclovir infusion bags are prepared in series in the Pharmacy Department by using the APOTECAchemo robot. Expiration dates are to be determined based on physicochemical and microbiological stability studies.

Purpose The aim of the study was to evaluate the microbiological stability of dose-banded, automatically prepared ready-to-administer infusion bags (10 per series) by media-fill simulation tests.

Material and methods The aseptic preparation of a series of 10 infusion bags was simulated with purchased double-strength growth medium TSB (BD^TM, Germany) and prefilled 250 mL 0.9% NaCl polyolefin infusion bags (Freeflex^®, Fresenius, Germany). After withdrawal of superfluous vehicle solution, 125 ml of TSB were added and a final volume of 250 ml achieved. The simulation process was performed with the APOTECAchemo robot on five consecutive days. In total, 50 infusion bags were filled, incubated and stored for 12 weeks (maximum intended storage interval) at room temperature. The media-filled bags were visually inspected for turbidity after 2, 4, 8, 10 and 12 weeks. After 4 weeks, 10 bags were randomly sampled and growth promotion tests performed by inoculation of S. epidermidis KH6 or S. aureus ATCC6538 suspensions in order to achieve a concentration of 10 CFU/mL, i.e. 2500 CFU/bag. During the simulation tests, airborne contamination was monitored with settle plates and microbial surface contamination with contact plates.

Results None of the 50 media-filled bags showed turbidity after an incubation period of 2 weeks and storage period up to 8 weeks, indicating the absence of microorganisms. Positive growth promotion tests proved the process reliability, since both bacteria species caused turbidity in all samples after 5 days of incubation. The environmental monitoring with settle/contact plates matched the recommended limits set for cleanroom Grade A zones, except in the loading area of the robot.

Conclusion Media-fill simulation tests and supplemental environmental monitoring of aseptic preparation of infusion bags in series by the APOTECAchemo revealed an adequate sterility level and a well-controlled aseptic procedure. The sterility was maintained over extended incubation and storage periods, thereby encouraging extended expiration dating.

No conflict of interest