A pharmaceutical composition suitable for use with a metered dose inhaler (MDI) comprises； (i) a drug component comprising at least one pharmaceutically acceptable salt of glycopyrrolate； and (ii) a propellant component comprising 1,1-difluoroethane (HFA-152a). Preferably, the glycopyrrolate is present as the bromide salt. Preferably, the composition further comprises at least one long acting beta-2-agoinst (LABA) (e.g. indacaterol, olodaterol, formoterol, vilanterol). Preferably, the composition additionally comprises at least one corticosteroid (e.g. budesonide, mometasone, beclomethasone, fluticasone). Preferably, the composition additionally comprises at least one surfactant compound (e.g. polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), oleic acid, lecithin). Preferably, the composition contains less than 5 ppm water. In preferred embodiments the propellant is entirely HFA-152a. The composition may contain ethanol as a polar excipient. Also claimed is a method of improving the stability of a pharmaceutical composition comprising propellant and glycopyrrolate through use of HFA-152a as propellant.
