A composition for use in an aerosol inhaler comprises an active material, a propellant containing a hydrofluoroalkane and a cosolvent. The composition further includes a low volatility component which is added to increase the mass median aerodynamic diameter (MMAD) of the aerosol particles on actuation of the inhaler. With the addition of the low volatility component, the MMAD of the aerosol particles may be comparable to the MMAD of aerosol particles of an aerosol inhaler including CFC as propellant.
