Sterile Preparations for Pharmaceutical Compounding



“Describes conditions and best practices to prevent critical harm to patients, which can be attributed to contaminated or improperly compounded sterile preparations (CSPs).”

The outlined standards apply to all persons who prepare CSPs. This also includes the areas in which CSPs are prepared which may include: pharmacies, treatment clinics, hospitals, healthcare institutions, etc.)

Cleaning & Disinfecting Pharmacy Controlled Environments


The preparation of CSPs is to be complemented with equally maintained sterility and a minimized introduction of particulate matter.”

“Environmental contact is one of the core sources of microbial contamination of CSPs.” While USP Chapter <797> provides best practices and minimum safety standards, Clean Air Essentials, offer the highest standard of cleaning and disinfecting products for compounding personnel preparing CSPs, who can be confident in knowing they are maintaining sterility and cleanliness to the compounding area.

Some of the sterile compounding duties include:

        • Antiseptic Hand Cleansing and Disinfecting of Non-sterile compounding services Maintain sterility of CSPs in ISO Class 5
        • Selection of appropriate protective garb
        • Maintain sterility of CSPs in ISO Class 5
        • Identify, weigh, and measuring of ingredients

It is important to recognize the contamination categories for CSPs, notably for their 3 levels of risk (low, medium and high) which can vary from harmful to life-threatening. While it is the responsibility of compounding personnel to be aware of the potential risks to the integrity of CSPs. It is also important to note that they are also responsible for the application of quality assurance practices, cleaning products and usage frequency. Proper product selection is important and should be done carefully.

Our knowledgeable advisors at Clean Air Essentials can equip you with the right product options and confidence in knowing your personnel are using the highest standard for cleaning. Quality Assurance practices may include:
  • Routine Disinfecting consistently minimizes microbial surface contamination.
  • Note: Facilities with ISO Class 5 may have an increased standardized process for cleaning.
  • Spot Check 1 (Personnel): Visual confirmation that all compounding personnel are wearing the appropriate PPE.
    • Review: All ingredients are correctly identified for compounding.
    • Spot Check 2 (CSPs):  Visual confirmation that there is an absence of leakage from bags, vials and proper labelling.



    Maintaining a clean and sanitary environment is paramount in various settings, and equipping personnel with the right supplies and knowledge is essential for effective cleaning practices. With the exception of tool handles and holders, all cleaning supplies such as wipers, sponges, pads, and mop heads should be low-tint. For areas within the PEC, supplies must be sterile. Tool handles and holders should undergo thorough cleaning and disinfecting before each use. Any disposable supplies used must be promptly discarded after completing each cleaning activity.

    In the case of reusable tools, it is imperative that they are constructed from materials that can be easily cleaned and have designated spaces known as Special Controlled Areas (SCAs) for usage. Remember to clean and disinfect reusable supplies before and after every use and dispose of tools that have been moved from its original SCA position to prevent the spread of contamination.

    Clean Air Essentials Guideline: During selection, avoid tools that are permeable, such as wood handles.

    Sterile cleaning and disinfecting agents and supplies can be reused for a specified time, as determined by the manufacturer or facility SOPs (Standard Operating Procedures), once opened.

    Adherence to these guidelines not only promotes a hygienic environment but also safeguards against potential health hazards. 

    Clean Air Essentials Guide for Cleaning and Disinfecting

    Primary Engineering Controls (PEC):

    • Page 15 of the USP <797> indicates that “Cleaning and disinfecting surfaces in the LAFWs, BSCs, CAIs, and CACIs are the most critical practices before the preparation of CSPs.
    • Consequently, such surfaces shall be cleaned and disinfected frequently, including at the beginning of each work shift, before each batch preparation is started, every 30 minutes during continuous compounding periods of individual CSPs, when there are spills, and when surface contamination is known or suspected from procedural breaches.”

    Apply the P-E-C Cleaning Method:

    Minimum Cleaning Frequency:
    • Beginning of each shift & compounding batch, no longer than 30 minutes following the previous surface disinfection of compounding activity”


    • Proper selection and application of sterile wipes provided by Clean Air Essentials


    • East-to-West” single-direction cleaning to ensure full disinfecting coverage.


    • Complete cleaning Hard to Reach Surfaces first, before cleaning large surfaces of the PEC

      Anteroom and the Buffer Room:


      Clean Air Essentials Guideline: It is important to separate the hardware supplies used for hazardous compounding and non-hazardous areas.



      Minimum Cleaning Frequency:
      • Daily


      • Clean and decontaminate your unit before and after operation using Clorox Fuzion and/or Sterile IPA 70%
      • How often should Isolator Sleeves be changed?
        • 3 Months for Hazardous Compounding
        • 6 Months for Sterile Compounding
        • *Note: that the interval may be shorter for heavier use

      Ceilings and Walls:

      • Page 16 of the USP <797> indicates that “In the buffer or clean area, ante-area, and segregated compounding area, walls, ceilings, and shelving shall be cleaned and disinfected monthly.”

      Cleaning Method: Eyes Up, Eyes Down (Top to Bottom)

      Minimum Cleaning Frequency:
      • Monthly
      • Prioritize cleaning ceilings first and work your way down. Be sure to clean irregular surfaces by hand with a dry wipe including air returns, outlets, shelving (Sterile Dry Wipes) and Clorox Fuzion.
      • For walls, apply the East-to-West single-direction cleaning to ensure full disinfecting coverage.
      • Ensure site protocols and SOPs are followed correctly.


        • Page 15 of the USP <797> dictates that “Floors in the buffer or clean area, ante-area, and segregated compounding area are cleaned by mopping with a cleaning and disinfecting agent once daily at a time when no aseptic operations are in progress.”

          It is essential to be mindful of the following:

          • Cleaning Materials Our sterile wipes or wiper rolls are recommended for cleaning.
            • *Note: Cleaning tools should be treated as single-use only. 
          • Floor Cleaning Disinfectants: “When the surface to be disinfected has heavy soiling, a cleaning step is recommended prior to the application of the disinfectant.”
          • Storage: Cleaning supplies used should be dedicated to that area, exclusively and not used in combination (i.e.) buffer or clean, ante and compounding areas.
            • *Note: Removal of supplies from areas should be for proper disposal purposes, only.

          Cleaning Method: “Far Out”

          Minimum Cleaning Frequency:
          • Daily
          • Begin cleaning at the farthest corner of the room, mopping backwards towards the door of entry.
          • Ensure to mop using the Essential-S Pattern, allowing solutions to settle for maximum disinfecting coverage.


          For more information regarding the minimum frequency of Cleaning and Disinfecting Compounding Areas, please refer to the table below.

          Location (Site):

          Minimum Cleaning Frequency

          Minimum Disinfecting Frequency

          Application of Sporicidal Disinfectant Frequency

          PEC and Equipment within PEC


          Daily, when compounding occurs. 

          This includes equipment and all interior surfaces.


          Daily, when compounding occurs. 

          This includes equipment and all interior surfaces.

          Monthly, for Category 1 & 2 CSPs 

          Weekly for Category 3 CSPs

          Removable Work Tray

          of PEC


          Daily cleaning of  tray surface on compounding days.

          Surface area beneath the tray should be cleaned monthly.



          Daily disinfecting of tray surface when compounding occurs.

          Surface area beneath the tray should be disinfected monthly.


          Monthly, for the following areas of the tray:

          • Work Surface

          • Beneath tray

          Counters, cleanable work surfaces (Outside of PEC)

          Pass-through Chambers


          Daily, when compounding occurs.

          Daily, when compounding occurs.


          Monthly, for Category 1 & 2 CSPs 

          Weekly for Category 3 CSPs



          Wall(s), door(s) and door frame(s)


          Storage Shelving and Bins

          Equipment outside PEC


          Monthly, when compounding takes place.

          Monthly, when compounding takes place.