Absence of Bacterial or Fungal Growth in Vials of Reconstituted Botulinum Toxin Type A After Storage

Abstract

Background: Botulinum toxin type A (BTX-A; Botox) is supplied as individual freeze-dried preparations that should be administered within 24 hours after reconstitution. To avoid wasting this expensive drug, some physicians have resorted to storing vials of reconstituted BTX-A beyond the recommended duration. However, there is insufficient evidence to indicate that the sterility of previously reconstituted BTX-A is maintained during storage.Objectives: the authors sought to determine whether bacterial and/or fungal proliferation occurred in vials of reconstituted BTX-A and subsequent storage of the remaining solution under refrigeration for 4 weeks.Methods: A portion of the contents of 88 consecutive 100-U vials of BTX-A was administered aseptically to 108 patients for essential blepharospasm, hemifacial spasm, or facial rejuvenation. the vials were then stored for 4 weeks in a refrigerator, after which the contents were transferred to various media (blood agar, chocolate agar, Sabouraud agar, brain-heart infusion medium, and thioglycolate broth) and assessed for bacterial and/or fungal growth by standard methods.Results: None of the BTX-A vials contained detectable bacterial or fungal contamination after 4 weeks of storage.Conclusions: Storing vials of reconstituted BTX-A for 4 weeks after administration to patients was not associated with detectable growth of bacteria or fungi.