title: Comparative study of biological activity of four botulinum toxin type A preparations in mice.
abstract: BACKGROUND
  Units of available botulinum toxin preparations are not interchangeable, and the dose-conversion ratios between such preparations remain controversial.
  
  
  OBJECTIVE
  To compare the efficacy and safety of four botulinum toxin type A preparations.
  
  
  METHODS
  Murine gastrocnemius compound muscle action potentials (CMAPs) were recorded before and after injecting the four botulinum toxin preparations (onabotulinumtoxinA, abobotulinumtoxinA, new botulinum toxin, and incobotulinumtoxinA).
  
  
  RESULTS
  In all preparations, CMAP amplitudes decreased until 4 days after receiving the injection and then gradually recovered. On postinjection day 84, the amplitudes returned to baseline in all groups except the high-dose groups. CMAP amplitude in the contralateral limb also decreased up to postinjection days 4 to 7 and then gradually returned to baseline by postinjection day 28.
  
  
  CONCLUSIONS
  The dose-conversion ratio between onabotulinumtoxinA and abobotulinumtoxinA was determined to be 1:2.6; previous reports of 1:3 were considered too high. A dose-conversion ratio between onabotulinumtoxinA and new botulinum toxin of 1:1 was deemed appropriate. OnabotulinumtoxinA and incobotulinumtoxinA demonstrated a dose-conversion ratio of 1:1.07. The efficacy of incobotulinumtoxinA was slightly lower than that of onabotulinumtoxinA. These dose-conversion ratios are applicable solely from an efficacy standpoint and not for safety. This study was conducted in mice, so it may not translate perfectly to human applications.
authors.affiliation: Department of Rehabilitation Medicine, St. Paul's Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea.
authors.forename: Myung Eun
authors.initials: ME
authors.lastname: Chung
authors.forename: Dae Heon
authors.initials: DH
authors.lastname: Song
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Park
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D019274:Botulinum Toxins, Type A / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007928:Lethal Dose 50; D051379:Mice; D008813:Mice, Inbred ICR; D018908:Muscle Weakness / Q000139:chemically induced; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology; D016037:Single-Blind Method; D013997:Time Factors
chemical_list: D009498:Neurotoxins; D019274:Botulinum Toxins, Type A; C542869:abobotulinumtoxinA; C545476:incobotulinumtoxinA