What is the primary reason for using a HEPA filter in a pharmacy compounding area?

The primary reason for using a HEPA (High-Efficiency Particulate Air) filter in a pharmacy compounding area is to maintain a sterile environment by removing airborne particles, including bacteria, viruses, and fungal spores, to prevent contamination of compounded sterile preparations (CSPs). Pharmacy compounding involves preparing medications that are not commercially available, and these preparations must be sterile to prevent infections in patients. HEPA filters are highly efficient at removing airborne particles, capturing at least 99.97% of particles 0.3 micrometers in size or larger. This level of filtration is essential for creating and maintaining a sterile environment in the compounding area, protecting the CSPs from contamination. USP (United States Pharmacopeia) <797> guidelines require the use of HEPA filters in primary engineering controls (PECs), such as laminar airflow workbenches (LAFWs) and compounding aseptic isolators (CAIs), to ensure the sterility of compounded medications. Without HEPA filtration, the compounding area would be susceptible to airborne contamination, increasing the risk of patient infections.