title: Reduced potency after refrigerated storage of botulitum toxin A: human extensor digitorum brevis muscle study.
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.
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, South Korea. njpaik@snu.ac.kr
authors.forename: Nam-Jong
authors.initials: NJ
authors.lastname: Paik
authors.forename: Kyle
authors.initials: K
authors.lastname: Seo
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Eun
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000494:pharmacology*; D004356:Drug Storage; D004576:Electromyography / Q000187:drug effects; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D009046:Motor Neurons / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000294:innervation; D009431:Neural Conduction / Q000187:drug effects; D010543:Peroneal Nerve / Q000187:drug effects; D011446:Prospective Studies; D012034:Refrigeration / Q000009:adverse effects*
chemical_list: D019274:Botulinum Toxins, Type A