A stable ready-to-use injectable pharmaceutical composition for reversing the effects of non-depolarizing neuromuscular blocking agents in a patient in need thereof, comprising (i) about 1 mg/mL of neostigmine or a pharmaceutically acceptable salt, solvate or hydrate thereof, (ii) about 0.2 mg/mL of glycopyrrolate or a pharmaceutically acceptable salt, solvate or hydrate thereof, (iii) a pharmaceutically acceptable liquid vehicle, (iv) a tonicity modifier;
- and (v) a pH adjusting agent;
- wherein the level of Glycopyrrolate Impurity C in the composition is less than 1% when stored at 40° C. and 75% relative humidity for 3 months;
- wherein the tonicity modifier is sodium chloride;
- and
- wherein the pH adjusting agent is sodium hydroxide, hydrochloric acid or a mixture thereof.