IACUC Approves Revised Guidelines on the Preparation, Storage, and Expiration of Injectable Medications

May 20, 2019

Expired drugs with additional clock icon

The Institutional Animal Care & Use Committee (IACUC), in close consultation with ULAM Faculty Veterinarians, has approved several revisions to the Guidelines on the Preparation, Storage, and Expiration of Injectable Medications.

Specifically, these revisions affect the expiration and beyond use dates of:

  • Mixed or diluted formulations —
    The expiration date for mixed or diluted formulations has been extended from 7 to 30 days after initial opening.
  • Sterile fluids used to provide IV fluid support —
    The expiration date for sterile fluids has been extended from 24 to 72 hours after initial opening.

Why Have Expiration Dates Been Extended?

In an effort to reduce waste and minimize study team burden while still safeguarding the research environment, the Unit for Laboratory Animal Medicine (ULAM) conducted a comprehensive internal study to evaluate the sterility and potency of several commonly-used anesthetic and analgesic drugs.

Led by Patrick A. Lester, DVM, MS, DACLAM, the results of the study yellow lock icon showed that all samples passed sterility at all time points, regardless of the temperature (room vs. refrigerated) or container type (glass vs. plastic).

Specifically, the following dilutions remained above 90% potency* after approximately 30 days:

  • Buprenorphine 0.03 mg/ml
  • Carprofen 1 mg/ml
  • Xylazine 1 mg/ml

Although diluted ketamine dipped below 90% potency at 30 days, using a 100 mg/kg dose
should still be within the specific dosage range for a mouse measuring 80 – 120 mg/kg.


Please review the complete Guidelines on the Preparation, Storage, and Expiration of Injectable Medications for more information, including a summary of all changes and how these changes may impact your research.

Questions or Concerns?

If you have specific questions or concerns or would like additional clarification on any aspect of the revised guidelines, please contact your ULAM Faculty Veterinarian. If you don’t know your faculty veterinarian, send an inquiry to ulam-questions@umich.edu and your question will be routed appropriately.

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