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Botulinum A toxins: units versus units
K Wohlfarth1, H Göschel, J Frevert
1Department of Neurology, Medical School of Hannover, Germany.
Naunyn-Schmiedeberg'S Archives of Pharmacology
|March 1, 1997
Summary
This study found no difference in the potency or effectiveness of two commercial botulinum neurotoxin type A (BoNT/A) preparations. Results from both animal models and human trials indicate that 1 unit of Botox is equivalent to 1 unit of Dysport.
Area of Science:
- Neurology
- Pharmacology
- Biotechnology
Background:
- Two commercial botulinum neurotoxin type A (BoNT/A) preparations are reputed to have different potencies.
- Anecdotal reports suggest variations in effectiveness between these products.
Purpose of the Study:
- To investigate and compare the efficacies and potencies of two commercial BoNT/A preparations.
- To determine if 1 unit of Botox is equivalent to 1 unit of Dysport.
Main Methods:
- In vitro testing using the mouse phrenic nerve-hemidiaphragm assay for clostridial toxicity.
- A double-blind trial in human volunteers involving injections into the Musculus extensor digitorum brevis.
- Recording of compound muscle action potentials (CMAPs) before and after injections.
Main Results:
- No significant difference in effectiveness was found between the two BoNT/A preparations in either in vitro or human trials.
- Dose-response curves for both products were identical in potency and correlated with previous toxicity tests.
- The time course of muscle paralysis and recovery was similar for both preparations, although faster recovery was observed at lower toxin concentrations.
Conclusions:
- The in vitro and human trial results are in excellent accord.
- 1 unit of Botox is equivalent to 1 unit of Dysport.
- The potency of commercial BoNT/A preparations is consistent across different testing models.