title: Establishment of alternative potency test for botulinum toxin type A using compound muscle action potential (CMAP) in rats.
abstract: The biological activity of botulinum toxin type A has been evaluated using the mouse intraperitoneal (ip) LD50 test. This method requires a large number of mice to precisely determine toxin activity, and, as such, poses problems with regard to animal welfare. We previously developed a compound muscle action potential (CMAP) assay using rats as an alternative method to the mouse ip LD50 test. In this study, to evaluate this quantitative method of measuring toxin activity using CMAP, we assessed the parameters necessary for quantitative tests according to ICH Q2 (R1). This assay could be used to evaluate the activity of the toxin, even when inactive toxin was mixed with the sample. To reduce the number of animals needed, this assay was set to measure two samples per animal. Linearity was detected over a range of 0.1-12.8 U/mL, and the measurement range was set at 0.4-6.4 U/mL. The results for accuracy and precision showed low variability. The body weight was selected as a variable factor, but it showed no effect on the CMAP amplitude. In this study, potency tests using the rat CMAP assay of botulinum toxin type A demonstrated that it met the criteria for a quantitative analysis method.
authors.affiliation: The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan; Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita-shi, Osaka 565-0871, Japan. Electronic address: torii@bact.med.osaka-u.ac.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Torii
authors.affiliation: The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Goto
authors.affiliation: The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakahira
authors.affiliation: The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ginnaga
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D019274:Botulinum Toxins, Type A / Q000633:toxicity*; D005260:Female; D007928:Lethal Dose 50; D057230:Limit of Detection; D051379:Mice; D008813:Mice, Inbred ICR; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D019274:Botulinum Toxins, Type A
keywords: Botulinum toxin; CMAP; ICH; Mouse ip LD(50); Quantitative analysis