Introduction: 

Media-fills, as a measure of aseptic competence, have been  required since the release of USP <797> in 2004. This compounding simulation challenge is an essential part of personnel assessments, administered to evaluate the aseptic skill and mastery of compounders. The media-fill exercise is applied both to newly trained novices with no compounding experience, experienced compounders, and anytime an evaluation is warranted including those part of a corrective or remediation process.

What does USP say regarding media fills? 

In the current version of USP 797 (November 2022), the media fill exercise is conducted every six months for Categories 1 and 2 sterile compounding and every three months for Category 3 (section 2.2 & 2.3). For the initial evaluation of personnel into compounding environments, the media fill is administered subsequent to a triplicate series of hand hygiene and garbing return demonstrations which also include three samplings of gloved-hand fingertip and thumbprints onto a media plate.  

What is a media fill challenge? 

A media fill challenge simulates an aseptic process which is common to the workflow process in a compounding facility. It should include a set of sequential manipulative steps which represent the most complicated of processes employed to compound a CSP. In some cases, this can mean that you may need to deviate from the manufacturer’s instructions included in commercially available kits to achieve an accurate simulation. If this is done, or if you purchase your own media fill components and design your own media-fill exercise, be sure to have an SOP to support your procedure.  

How then should I design the exercise? 

Section 2.3 of USP <797> states: “When performing a media-fill test, simulate the most difficult and challenging compounding procedures and processing conditions encountered by the person replacing all the components used in the CSPs with soybean–casein digest media.”  

To achieve this, the designated person must determine the level of complexity your test will carry for the experience level of the candidate being tested. The spirit of USP 797 suggests that a newly trained employee should be most rigorously tested to ascertain their physical and psychological tolerance of the compounding environment: continuous machine noise, gown tolerance, the feeling of confinement and the ability to compound for extended periods of time among others. Experienced compounders (on-going validation) could be tested on a single compounding run of 60 min duration including hand hygiene, garbing and fingertip sampling. The initial validation can run 2-3 times longer with many more components and steps. This test could require two to three hours including initial hand hygiene, garbing and gloved hand finger and thumbprint sampling in triplicate. 

A good example of a well-designed test is Lab Safety’s Valiteq RL-2 kit (old version’s risk level 2 or medium risk). This test is already packaged and sold as a triplicate test and contains a variety of components that represent most compounding processes. You will find three sets of ampules, dry powder for reconstitution, a single use vial and a multiple use vial. The DP can run three ongoing validation or one initial validation with each kit. A note of warning: The kit comes in a cardboard box with a styrofoam insert which protect the components from breakage during shipping. All components must be removed from shipping cartons and disinfected in the unclassified space prior to introduction into anterooms. 

In terms of documentation, include the following for each participant: The test worksheet with the test steps, the media fill manufacturer, lot number and expiration date as well as the certificate of analysis included with the kit. 

Results: Is a turbidity-free MF the only consideration for a successful evaluation?

Media fill tests are infrequently turbid. This could be because the test is too simple or simply because a participant must really do something grossly irregular to inoculate the media with his or her own skin cells or other contaminant. Therefore, the observation of the participant’s behavior and aseptic process becomes as important or more important than the media fill exercise. Even if the media sample is clear, it’s crucial to observe the participant’s adherence to aseptic protocols and correct any deviations. Clear media fill results should not automatically be considered a passing grade. Instead, use this as an opportunity to reinforce fundamental aseptic techniques, especially for experienced compounders. 

Conclusion

Media fills are an invaluable tool for validating aseptic techniques, but their design and interpretation are critical to their success. By carefully crafting the exercise, choosing the appropriate kit, and thoroughly assessing both results and behaviors, you ensure not only compliance but excellence in your sterile compounding operations. 

Released October 2024

About the Author

Luis Hernandez, RPh, BCSCP, is a certified sterile compounding pharmacist and the founder of Seven97 Training Solutions. Dedicated to advancing USP 797 pharmaceutical training, validation, and certification, Luis aims to promote and inspire excellence in aseptic processing, medication and patient safety, and regulatory compliance.

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