Using a medium-fill simulation to evaluate the microbial contamination rate for USP medium-risk-level compounding

Area of Science:

• Pharmaceutical compounding
• Microbial contamination
• Sterile preparations

Background:

• Complex sterile preparations require meticulous aseptic technique.
• Assessing contamination rates is crucial for patient safety in healthcare settings.
• United States Pharmacopeia (USP) guidelines define risk levels for compounding.

Purpose of the Study:

• To estimate the microbial contamination rate in complex, multiple-step, medium-risk-level sterile compounding.
• To evaluate the aseptic technique of pharmacists and technicians during compounding.
• To identify potential sources of microbial contamination in sterile preparations.

Main Methods:

• Compiled results from 539 aseptic technique evaluations conducted in 2002-2003.
• Simulated compounding of USP medium-risk-level sterile preparations using sterile growth medium.
• Incubated compounded preparations for 14 days to detect microbial growth.

Main Results:

• Overall microbial contamination rate was 5.2% (28 out of 539 evaluations).
• Pharmacists demonstrated a lower contamination rate (4.4%) compared to technicians (6.2%).
• Inadvertent touch contamination was identified as a probable primary source of microbial growth.

Conclusions:

• Aseptic technique evaluations simulating USP medium-risk compounding revealed a 5.2% contamination rate over two years.
• Differences in contamination rates between pharmacists and technicians highlight the importance of training and technique.
• Minimizing touch contamination is critical for reducing microbial contamination in sterile compounding environments.