Microbial Integrity Study of Preservative-Free Alfaxalone (Alfaxan) in a Multi-Use System with Two Storage Conditions and Three Handling Techniques
Alfaxalone (Alfaxan-CD, Jurox Pty Ltd.) is a neurosteroid that agonizes gamma-aminobutyric acid A (GABAA) receptors inducing anesthesia in numerous species when administered intravenously or intramuscularly.1 Alfaxalone has been reported to be a less favorable medium for bacterial growth when compared to propofol.2 The Australian Alfaxan-CD labeling permits broached vial storage at 4°C for up to 7 days, if contamination is avoided; however, the U.S. Food and Drug Administration prohibits the use of Alfaxan beyond 6 hours, because it is preservative free. The objective was to evaluate the microbial integrity of preservative-free, cyclodextrin-based alfaxalone (Alfaxan-CD) in a multi-use system, over 14 days, with two storage conditions (1. room temperature at 21°C; 2. refrigerated at 4°C) and three handling techniques (1. nonclosed dispensing port; 2. closed-system transfer device; 3. vial stopper). Methodology comprised six treatment groups (n=3 per group), and 0.5 ml per vial was withdrawn daily for 14 days. The samples were placed immediately in tryptic soy broth and sub-cultured onto sheep’s blood agar plates for objective evaluation of microbial growth. The results revealed no microbial growth in handling technique for groups 1 and 2 at either storage condition, for up to 7 days. These findings support the Australian Alfaxan-CD labeled discard time of 7 days if stored at 4°C. Extending the discard time of Alfaxan minimizes drug waste and the subsequent environmental impact of unused drug, and it offers a practical anesthetic alternative for use in veterinary practices across the United States.
The authors would like to thank Jurox Pty Ltd., as well as the Department of Clinical Sciences, the Department of Population Health and Pathobiology, and the Pharmacy Services at North Carolina State University Veterinary Hospital for their support and assistance facilitating this project completion.
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