A compound of formula (I) wherein R1 is selected from H, F, Cl, Br, CF3, C1-C6 alkoxy and OH; R2 is selected from H and C1-C6 alkyl; n is 1-12; m is O or 1; Y is selected from CH2, NR3, (NR3R4)+X, O and S; R3 and R4 are independently selected from H and C1-C4 alkyl; and X″ is selected from phannaceutically acceptable anions. A method of preparing the compound, its use as a pharmaceutical, and a method of treatment.