Pyridazinone compounds effective as beta-2-adrenoreceptor agonists as well as PDE4-inhibitors

The compounds of formula (I) wherein Ar1, A, R6, R7, R8 and Ar2 are as defined in the specification, have valuable pharmacological properties which make them commercially utilizable. As these compounds providing selective PDE4 inhibition combined with b2-adrenoceptor agonist activity they are suitable on the one hand as bronchial therapeutics (for the treatment of airway obstructions on account of their dilating but also on account of their respiratory rate or respiratory drive-increasing action), but on the other hand especially for the treatment of disorders, in particular of inflammatory nature, e. g. of the airways, of the skin, of the central nervous system, of the intestine, of the eyes and of the joints, which are mediated by mediators such as histamine, PAF (platelet-activating factor), arachidonic acid metabolites such as leukotrienes and prostaglandins, cytokines, interleukins, chemokines, alpha-, beta-and gamma-interferon, tumor necrosis factor (TNF) or oxygen radicals and proteases.