Response to Commentary by W. Jost on: Pharmaceutical, Biological, and Clinical Properties of Botulinum Neurotoxin Type A Products

Qualitative and Quantitative Detection of Botulinum Neurotoxins from Complex Matrices: Results of the First International Proficiency Test

In the framework of the EU project EQuATox, a first international proficiency test (PT) on the detection and quantification of botulinum neurotoxins (BoNT) was conducted. Sample materials included BoNT serotypes A, B and E spiked into buffer, milk, meat extract and serum. Different methods were applied by the participants combining different principles of detection, identification and quantification. Based on qualitative assays, 95% of all results reported were correct. Successful strategies for BoNT detection were based on a combination of complementary immunological, MS-based and functional methods or on suitable functional in vivo/in vitro approaches (mouse bioassay, hemidiaphragm assay and Endopep-MS assay). Quantification of BoNT/A, BoNT/B and BoNT/E was performed by 48% of participating laboratories. It turned out that precise quantification of BoNT was difficult, resulting in a substantial scatter of quantitative data. This was especially true for results obtained by the mouse bioassay which is currently considered as "gold standard" for BoNT detection. The results clearly demonstrate the urgent need for certified BoNT reference materials and the development of methods replacing animal testing. In this context, the BoNT PT provided the valuable information that both the Endopep-MS assay and the hemidiaphragm assay delivered quantitative results superior to the mouse bioassay.

Aesthetic use of BoNT: Options and outcomes

There are a multitude of uses for BoNT in the aesthetic realm. Efficacy has been shown in softening glabellar creases, crows feet, forehead rhytides, and in correcting facial asymmetries, including mild eyelid ptosis. Facial shape can be altered through injections of BoNT into masseter, and smiles can be altered with BoNT. Clinical examples of the above will be shown, as well as adverse outcomes with inaccurate injection techniques.