Reduced potency after refrigerated storage of botulitum toxin A: Human extensor digitorum brevis muscle study

Authors

  • Nam-Jong Paik MD, PhD,

    Corresponding author
    1. Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, South Korea
    • Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong Bundang-gu, Seongnam 463-707, South Korea
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  • Kyle Seo MD, PhD,

    1. Botulinum Institute and Modelo Dermatology and Laser Clinic, Seoul, South Korea
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  • Hee Chul Eun MD, PhD

    1. Department of Dermatology, Seoul National University College of Medicine, Seoul,South Korea
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Abstract

To determine whether the potency of botulinum toxin A (BTA) decreases after being reconstituted with normal saline and stored in refrigerator, we injected one side of the extensor digitorum brevis muscle with 2.5 units of botulinum toxin A that had been immediately reconstituted with saline, and the contralateral side with identical material that had been reconstituted and stored in a refrigerator for preselected periods (1, 2, and 4 weeks) in 32 healthy volunteers. Mean compound muscle action potential amplitudes expressed as a percentage of the baseline amplitude were more reduced in sides injected with immediately reconstituted BTA than in sides injected with BTA stored for 1 week or more (P < 0.05). No bacterial growth was observed in any stored BTA samples. Storage of reconstituted BTA at low temperatures may affect the potency of the toxin. Therefore, the use of BTA after refrigerated storage is not recommended. © 2006 Movement Disorder Society

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