combined composition of formoterol and glycopyrronium bromide solution in stable pressurized aerosol

It relates to a pharmaceutical composition in aerosol solution for use in a pressurized metered dose inhaler comprising: a) a glycopyrronium bromide dosage between 5 and 26 ug per actuation; b) formoterol, or a salt thereof or a solvate of said salt, with a dosage between 1 and 25 ug per actuation; c) a propellant consisting of a HFA; d) a cosolvent; e) a mineral acid as a stabilizer in a useful quantity. This composition is contained in an aerosol can coated internally by a resin comprising a copolymer of fluorinated ethylene propylene (FEP). In a preferred aspect, the mineral acid is 1M hydrochloric acid, in an amount between 0.15 and 0.28 ug / ul as a stabilizer; and cosolvent is ethanol. In another aspect, said composition comprises optionally one or more pharmaceutically active ingredients selected from beta-2 agonists; for inhalation corticosteroids (beclomethasone dipropionate, budesonide, fluticasone propionate, triamcinolone, prednisone, etc.); antimuscarinic agents, and phosphodiesterase inhibitors-4. Storing said composition in aluminum cans coated internally as noted above, minimizes the amounts of degradation products (particularly DP3) during its shelf life, even below the threshold of detection after storage under severe conditions of temperature and humidity.