Background In order to adapt Spanish regulations to the principles set out in the European Resolution CM/ResAP(2011)1 on quality and safety assurance requirements for medicinal products prepared in pharmacies, a guideline on pharmacy sterile preparations at hospital pharmacies (GPSP) was published by the Ministry of Health in June 2014. The guideline includes a risk based decision matrix to determine the potential risk of microbial contamination of pharmacy sterile preparations (PSPs) and sets beyond use dates (BUDs). According to the GPSP requirements, if recommended BUD limits are exceeded, each batch of PSP must be tested for sterility.

Purpose To determine the risk of microbial contamination of pharmacy sterile preparations according to current recommendations and to adapt beyond use dates.

Material and methods Risk of microbial contamination was determined for PSPs prepared in a grade C environment at our pharmacy in 2014. No batch was tested for sterility.

PSPs were classified by dosage form. A database was created to evaluate the 6 risk based decision matrix criteria: preparation process, route of administration, drug safety profile, units per batch, microbial contamination susceptibility and distribution.

According to the determined risk, GPSP recommended BUDs were set for each preparation and compared with the previous defined storage requirements.

Results 62 PSPs were evaluated: 18 individualised intravenous solutions, 11 standardised intravenous solutions, 6 subcutaneous preparations, 8 PSPs prepared from non-sterile components that were terminally sterilised, 15 ophthalmic preparations and 4 syringes for intravitreal injection.

According to the risk based decision matrix, we obtained: 21 low risk (most individualised intravenous solutions, subcutaneous preparations), 18 medium risk (standardised intravenous solutions, intravitreal injections) and 23 high risk PSPs (ophthalmic solutions, PSPs prepared from non-sterile components).

When comparing GPSP recommended BUDs and storage conditions with the previously defined BUDs, 21 (100%) low risk and 14 (78%) medium risk PSPs met the GPSP recommendations. BUDs of 4 (22%) medium risk preparations were shortened to comply with GPSP recommendations. In order to establish an extended BUD for 23 (100%) high risk PSPs, each batch must be tested for sterility.

Conclusion The GPSP proposed risk based decision matrix is a useful tool to determine the potential risk of microbial contamination of PSPs. Compliance with GPSP contributes to increased sterile compounding quality and protects the health of patients.

No conflict of interest.