Jerry Fahrni

Three concepts that create a lot of confusion: stability, beyond-use date, expiration

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Jerry Fahrni

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The differences between stability, beyond-use date (BUD), and expiration for compounded sterile preparations (CSPs) causes a lot of confusion. I’m not even certain that I fully understand their roles in day to day pharmacy operations. With that said, I think the key is for everyone to at least understand and agree that the BUD of a CSP is not the same as the expiration date.

Here’s how I understand it:

Stability is based on the chemical stability of the solute in solution, i.e. ingredients alone or in combination. This is what the Handbook on Injectable Drugs is all about, i.e. loss of drug potency/activity in solution.

Expiration date is defined by the FDA and identified by the product manufacturer.  Basically, it’s the shelf-life of the drug when properly stored. The expiration date no longer applies once the manufacture’s container is opened and the drug product is transferred to another container for dispensing or repackaging. Pharmacy uses “expiration date” loosely as we are not manufacturers. Most often I see pharmacies use expiration date in place of stability, i.e. the drug is good in solution for “this long”.

Beyond-use date (BUD) is assigned by the pharmacy for a CSP and is an arbitrary date/time found in USP <797> and adopted by many boards of pharmacy. BUD is based on sterility, stability. The BUD identifies the time by which a preparation – once mixed – must be used, i.e. “hung”. Once the CSP is hung on a patient, the BUD goes out the window and no longer applies. USP <797> does not address what to do with a CSP once it is hung on a patient. So something can have a BUD of 12-Hours, but be stable much longer. Pharmacies can extend BUDs, but only after independent sterility testing performed according to USP <71>, or in some cases when appropriate literature sources are used.

In summary, the BUD is not the expiration date, nor the stability of a preparation. Nurses must hang a CSP before the BUD is reached. The CSP can continue to hang on the patient until the “Expiration Date” is reached.

I would love to hear how facilities are dealing with these three concepts. Does your facility use a BUD and expiration on CSP labels?

Comments

2 responses to “Three concepts that create a lot of confusion: stability, beyond-use date, expiration”

  1. Maxime Thibault

    I agree with your interpretation. However, to properly calculate and label all those dates, the software we use has to support it, especially IV workflow software.

    Still, it seems weird to me that the BUD would go out the window when a CSP (or even a commercial drug, for that matter) is hung to the patient. There are strict guidelines for TPN, lipid emulsions and propofol but for other drugs there are no specific recommendations.

    It seems to me that microbiological stability should be even more important once a drug container is plugged in and could potentially be contaminated by all the manipulations that go on around the patient.

    In pediatrics and in the NICU, some drugs packaged for adult patients could potentially go on infusing for ridiculous amounts of time, like commercial 100 units/mL 250 mL heparin bags. At our center, we have arbitrarily decided on a max hang time of 96 hours for commercial drugs (to match tubing changes), 48 hours for pharmacy CSPs and 24 hours for drugs prepared outside of the pharmacy (and we follow recommandations for TPN, lipids and propofol). But this is just us, I wonder what other hospitals are doing about that.

  2. Jerry Fahrni

    You’re comments are interesting to me.

    I can see how you would view the BUD and handing on patients. I felt the same way for a while, but later changed my thinking based on several factors. One thing to remember is that the BUD is only for those items that are made in ISO class 5 conditions. In addition, they’re arbitrary. The next revision of USP <797> should clarify some of the confusion.

    How long an infusion hangs should be handled by the facility via P&P. I don’t think anything should hang for longer than 24 hours, much less 96 hours. I just feel as though you’re playing with fire.

    Anyway, interesting topic for discussion. I get a lot of variety when speaking to hospitals. It’s clear that the rules are unclear.

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