Botulinum neurotoxins are one of the most potent toxins known to man. Current 
methods of detection involve the quantification of the toxin but do not take 
into account the percentage of the toxin that is active. At present the assay 
used for monitoring the activity of the toxin is the mouse bioassay, which is 
lengthy and has ethical issues due to the use of live animals. This report 
demonstrates a novel assay that utilises the endopeptidase activity of the toxin 
to detect Botulinum neurotoxin in a pharmaceutical sample. The cleaving of 
SNAP-25 is monitored via UV-Visible spectroscopy with a limit of detection of 
373 fg/mL and has been further developed into a high throughput method using a 
microplate reader detecting down to 600 fg/mL of active toxin. The results show 
clear differences between the toxin product and the placebo, which contains the 
pharmaceutical excipients human serum albumin and lactose, showing that the 
assay detects the active form of the toxin.