Method for determining the quantity of a pre-synaptic neuromuscular blocking substance in a sample

摘要

Described is a method for determining the quantity of pre-synaptic neuromuscular blocking substance (notably botulinum toxin) contained in a sample. In one aspect the method comprises the following steps: (i) determining the minimum voltage Vm needed to induce the contraction of muscle tissue, said muscle tissue being connected to an electrical stimulator through a motor nerve and preferably immersed in an oxygenated physiological buffer containing glucose; (ii) adding the sample containing the pre-synaptic neuromuscular blocking substance; (iii) electrically stimulating, at a voltage at least equal to Vm, the muscle tissue at certain time intervals by electrical stimulations which comprise stimulations lasting a time tS separated from each other by periods lasting a time tP during which no stimulation is exerted, wherein the time tS from 50 µs to 500 ms, the time tP is from 0.1 to 10 s and the ratio tS/tP is from 1:2 to 1:50,000; (iv) comparing the effect induced by the sample to the effect induced by a reference substance and thereby determining the quantity of the pre-synaptic neuromuscular blocking substance in the sample.