Embodiments of the present disclosure relate to a chemical entity formed by reaction of components B and C, wherein component C is a moiety comprising one or more amine groups, and component B is a compound of Formula (I): wherein, A is a core moiety; L is an optional linker; R.sup.1 and R.sup.2 are independently selected from H and C.sub.1-5 alkyl; or R.sup.1 and R.sup.2 together with the C atom to which they are attached combine to form a C.sub.4-7 cycloalkyl ring or a 4-7 membered heterocyclic ring, both of which are optionally substituted on an available atom by one or more groups selected from C.sub.1-2 alkyl and oxo; n Sis O or 1; and m is an integer of at least 1. In one embodiment, at least a proportion of the thiol (SH) groups in the chemical entity have been converted to S-nitrosothiol (SNO) groups.