The invention relates to compounds of formula (I) in which R is selected from halogen, alkyl, alkoxy, aryl and heteroaryl; R1 is selected from 2-hydroxyethyl, 2,3-dihydroxypropyl, 3-hydroxypropyl, 2,2-dihydroxyethyl, 3,3-dihydroxypropyl, 1,3-dioxolane-ethyl, 1,3-dioxane-methyl, 1,3-dioxolane-methyl, 1,3-dioxane-ethyl, 3-fluoro-2-hydroxypropyl, 3-carboxy-2-hydroxy-propyl, 3-chloro-2-hydroxypropyl, 2-hydroxypropyl, 2-hydroxy-propen-2-yl, morpholinoethyl, piperazinoethyl, hydroxymethyl, benzyl, 4-(hydroxymethyl)benzyl, 4-chlorobenzyl, 4-fluorobenzyl, and 4-hydroxybenzyl. R2 is te/t-butyl or trifluoromethyl; R3 is independently selected from hydrogen, carboxy, cyano, alkyl or hydroxyalkyl, The compounds of formula (I) can be used for the preparation of pharmaceutical compositions for the therapy of inflammatory states, such as chronic neuropathic pain, over-active bladder syndrome, tumor pain, hemorrhoids, inflammatory hyperalgesia, post-intervention pain, dental extraction, airway and gastro-intestinal diseases.