The twin impinger: a simple device for assessing the delivery of drugs from metered dose pressurized aerosol inhalers

Abstract

The development is described of the twin impinger, a two-stage separation device for assessing the drug delivery from metered dose inhalers and other oral inhalation delivery devices. The discharged aerosol is fractionated by firing through a simulated oropharynx and then through an impinger stage of defined aerodynamic particle size cut-off characteristics. The fine (pulmonary) fraction which penetrates is collected by a lower impinger. It is demonstrated that this device is able to assess individually the fine particle delivery of both components of two-drug aerosols. Formulations showing undue agglomeration or serious crystal growth of drug are readily detected. The twin impinger is shown to be a valuable device for routine quality assessment of aerosols during product development, stability testing and for quality assurance and comparison of commercial products.

Formulations generated from ethanol-based proliposomes for delivery via medical nebulizers

“…The twin impinger (Hallworth & Westmoreland 1987), also known as the two-stage impinger or the Single Stage Glass Impinger, was set up with a flow rate of 60 L min À1 and isotonic NaCl (0.9%) as the collection medium. Cholesterol-containing liposomes prepared from proliposomes by dispersion in isotonic sucrose solution (5 mL) were placed in the nebulizer with the mouthpiece directed into the 'throat' of the impinger.…”

The formulation of powder inhalation systems containing a high mass of nedocromil sodium trihydrate

“…20 Although Apparatus A provides limited particle size distribution data, it has been used extensively to characterize and compare systems for inhalation. 15,18 A modi®ed stage 1 jet of internal diameter 11.6 mm was manufactured (University of Bath, Bath, UK) to give an effective cutoff diameter for 50% of the aerosol mass (ECD 50 ) of 5.3 AE 0.3 mm at 60 L/min; validated with monosized methylene blue droplets produced with a vibrating ori®ce aerosol generator (AEA Technology, Harwell, UK).…”

Physicochemical Factors Governing the Performance of Nedocromil Sodium as a Dry Powder Aerosol

“…Apparatus A has an effective cutoff diameter for 50% of the aerosol mass (ECD 50 ) of 6.4 m at the prescribed flow rate of 60 L/min, and divides the aerosol into two fractions. 9 Providing the apparatus conforms to impactor theory, this cutoff value can be obtained at other flow rates by altering the internal diameter of the jet within stage 1 of the impinger according to the following equation:…”