[Different botulinum toxins and their specifications]

Abstract

Botulinum neurotoxin A was the first developed for therapeutic and then esthetic uses, Botox first and then Dysport. These two products differ on a few points, explaining their nonequivalence of units: American and British tests of the mouse LD50 units based on solutions that were not identical and 500microg vs 150microg serum albumin dose in the excipient. The neurotoxin- accessory protein complexes were also different: 900 kDa homogeneous for Botox, 500 kDa heterogeneous for Dysport, giving greater diffusion for Dysport, but this is under debate and could result from an excessive conversion ratio. Clinical comparative studies, often with weak methodology, have defined an ideal ratio between these two products, guaranteeing efficacy, but without an overly pronounced diffusion. In the first publications for neurological and ophthalmological indications, the conversion ratio between Dysport and Botox was high, 4:1, and sometimes higher. However, today, particularly for cosmetic indications, the trend is toward a much lower ratio, 2.5:1, or perhaps less for dyshidrosis. This lower ratio has an economic incidence: Dysport is less expensive and therefore more competitive. The price of Dysport's cosmetic product, Azzalure, compared to the price of Vistabel, which is Botox's cosmetic presentation, has not yet been defined in France. The other A toxins, Xeomin, and the Asian toxins, MyoBloc (botulinum toxin type B), tested compared to Botox, have a slightly lower efficacy.