A neuromuscular blocking agent of formula (I) ** Formula ** in which each of R1 and R2 is independently selected from the group consisting of hydrogen and halogen, and R1 and R2 may be arranged in a cis or trans configuration in the two double bond carbon atoms to which R1 and R2 are respectively attached； T is selected from the group consisting of CH2 and CH3, in which if T is CH3, the phenyl group with the substituents X1-X5 is not present； B is selected from the group consisting of CH2, O, NR, and a direct single bond, wherein R is H, (C1-6) alkyl or acyl (C1-6)； n1 and n2 are each independently equal to 0, 1, 2 or 3； each of X1, X2, X3, X4 and X5 is independently at each occurrence hydrogen, hydroxy or methoxy, or any two adjacent X1, X2, X3, X4 or X5 together form a methylenedioxy or ethylenedioxy group； each of Y1, Y2, Y3, Y4 and Y5 is independently at each occurrence hydrogen, hydroxy or methoxy, or any two adjacent Y1, Y2, Y3, Y4 or Y5 together form a methylenedioxy or ethylenedioxy group； each of Z1, Z2, Z3 and Z4 is independently at each occurrence hydrogen hydroxy or methoxy, or any two adjacent Z1, Z2, Z3 or Z4 together form a methylenedioxy or ethylenedioxy group； W is selected from the group consisting of methyl and a benzyl group of the formula: ** Formula ** in which each of A1, A2 A3, A4 and A5 is independently at each occurrence hydrogen or methoxy, or two A1, A2 A3 , Any adjacent A4 or A5 together form a methylenedioxy or ethylenedioxy group, and a wavy line indicates a bonding point； and, wherein each QΘ is a pharmaceutically acceptable anion independently selected.Un agente bloqueante neuromuscular de fórmula (I)**Fórmula** en la que cada uno de R1 y R2 está seleccionado independientemente del grupo que consiste en hidrógeno y halógeno, y R1 y R2 pueden estar dispuestos en una configuración cis o trans en los dos átomos de carbono de doble enlace a los que R1 y R2 están respectivamente unidos； T está seleccionado del grupo que consiste en CH2 y
