Comparison of the primary rat spinal cord cell (RSC) assay and the mouse bioassay for botulinum neurotoxin type A potency determination.

Introduction: Botulinum neurotoxin (BoNT) type A is increasingly used in humans for pharmaceutical and cosmetic purposes. Currently, the standard assay used to determine potency of clinical samples, and the only assay approved by the FDA, is the in vivo mouse bioassay (MBA). However, due to several drawbacks of this assay (relatively large error, high cost, no standardization, requirement of high technical expertise, and use of large numbers of mice), there is an increasing need to replace this assay.

Extreme sensitivity of botulinum neurotoxin domains towards mild agitation.

Botulinum neurotoxins (BoNTs) and their fragments are targets of therapeutic developments and are increasingly used as therapeutic, prophylactic, and research reagents. However, published data on their properties vary widely. In order to gain a better understanding of these variations, we initiated a systematic investigation of the stability parameters of catalytic light chains (Lc) as well as of cell surface binding domains (Hc) of the neurotoxin.