The present invention relates to an aqueous composition comprising: (i) a quaternary ammonium neuromuscular blocking agent； and (ii) an excipient selected from a polyhydroxy acid of the following formula: HO-CH2-[CH(OH)]n-COOH, wherein n is an integer from 1 to 8, an intramolecular lactone of said polyhydroxy acid or a mixture thereof. Furthermore the present invention relates to a liquid pharmaceutical composition comprising or consisting of said aqueous composition and a method for producing said aqueous composition comprising the steps of: a) providing a quaternary ammonium neuromuscular blocking agent wherein said quaternary ammonium neuromuscular blocking agent is optionally freeze-dried, b) providing an excipient selected from a polyhydroxy acid of the following formula: HO-CH2-[CH(OH)]n-COOH, wherein n is an integer from 1 to 8, an intramolecular lactone of said polyhydroxy acid or a mixture thereof, wherein said excipient is optionally freeze-dried, c) mixing the quaternary ammonium neuromuscular blocking agent of step a) and the excipient of step b) in water to give an aqueous composition. In addition, the present invention relates to the use of a polyhydroxy carboxylic acid of the following formula: HO-CH2-[CH(OH)]n-COOH, wherein n is an integer from 1 to 8, an intramolecular lactone of said polyhydroxy acid or a mixture thereof for stabilizing an aqueous composition comprising a quaternary ammonium neuromuscular blocking agent. The present invention also refers to a container containing the aqueous composition or the liquid pharmaceutical composition of the present invention. It furthermore relates to a kit comprising said compositions. Preferred embodiments are apparent from the dependent claims.
