Each 3 mL vial of DuoNeb contains 3.0 mg (0.1%) of albuterol sulfate (equivalent to 2.5. mg (0.083%) of albuterol base) and 0.5 mg (0.017%) of ipratropium bromide in an. isotonic, sterile, aqueous solution containing sodium chloride, hydrochloric acid to adjust. to pH 4, and edetate disodium, USP (a chelating agent).