An inhalable powder formulation comprising a compound of general formula (II) ** Formula ** wherein: Z is selected from the group consisting of (CH2) m where m>； = 0, 1 or 2； and CR4R5 wherein R4 is independently selected from H or a linear or branched alkyl (from 1 to 4 carbon atoms) optionally substituted by one or more halogen atoms or by a cycloalkyl (from 1 to 4 carbon atoms), and R5 it is independently selected from the group consisting of straight or branched alkyl (from 1 to 4 carbon atoms), optionally substituted by one or more halogen atoms； - phenyl； - benzyl； - NH2； and - HNCOOR ', wherein R' is linear or branched alkyl (from 1 to 4 carbon atoms) optionally substituted by one or more halogen atoms. R1 and R2 are different or equal and are independently selected from the group consisting of - H； - linear or branched (from 1 to 6 carbon atoms) alkyl, optionally substituted by one or more substituents selected from halogen, cycloalkyl (from 3 to 7 carbon atoms) or cycloalkenyl (from 5 to 7 carbon atoms)； - cycloalkyl (from 3 to 7 carbon atoms)； - cycloalkenyl (from 5 to 7 carbon atoms)； - linear or branched alkenyl (2 to 6 carbon atoms)； and - linear or branched alkynyl (2 to 6 carbon atoms). A is a phenyl optionally substituted by one or more Rx groups, or A is a heteroaryl ring optionally substituted by one or more Rx groups, wherein A is a heteroaryl ring selected from the group consisting of pyrrole, pyrazole, furan, thiophene, imidazole , oxazol, isoxazol, thiazole, pyridine, pyrimidine, pyrazine, pyridazine and pyran, in which the optional substituent Rx in the ring A system may be one or more, may be the same or different, and is independently selected from the group that it consists of: - linear or branched alkyl (1 to 6 carbon atoms), optionally substituted by one or more halogen or cycloalkyl atoms (3 to 7 carbon atoms)； - linear or branched alkenyl (2 to 6 carbon atoms), optionally substituted by one or more cycloalkyl (3 to 7 carbon atoms)； -
