Anderson Cascade Impactor

Andersen Cascade Impactor (ACI)

(USP App 1 & 3, EP App D)

The 8-stage Andersen Cascade Impactor (ACI) is the most frequently used instrument for the testing of inhaler products within the Pharmaceutical Sector. Westech ACIs are specifically designed to meet the highest criteria laid down in the various.

Pharmacopoeias for characterising aerosol clouds emitted by inhalers. By analysing the drug deposited on the individual stages and the final filter, the Fine Particle Fraction, the Fine Particle Dose, the Mass Median Aerodynamic Diameter (MMAD) and Geometric Standard Deviation (GSD) can all be calculated. Apparatus D of the EP and Apparatus 1 & 3 of the USP clearly define the specifications of the Westech 8-stage impactor for use in the testing of MDIs and DPIs.

Detailed specification

  • Cascade impactors are multi-jet, multistage devices operating at constant flowrates that allow the characterisation of an aerosol in terms of its particle size distribution.
  • Westech produces three main configurations of the 8-stage non-viable impactor – designed for flowrates of 28.3, 60 and 90 L/min – and all are available in a variety of materials including Aluminium, 316 Stainless Steel and Titanium. Conversion kits for 60 and 90 L/min allow the standard 28.3 lpm impactor to be upgraded to the higher flowrates.
  • All Westech 8-stage Non-Viable impactors are quality controlled to extremely high tolerances by the use of a vision inspection instrument – Impactor Vision Inspection System (IVIS). Developed by Westech personnel (in conjunction with Specac Ltd, UK) this unique instrument is specifically designed for the measurement of the area, diameter and shape of the jets of Westech impactors.
  • Our history in the development of the 8-stage Andersen Cascade impactor gives us an unrivalled, intimate knowledge of the precision required to produce impactors with a guaranteed 100% of all jets being significantly within the required tolerances laid down in the various pharmacopeia.

Included in the standard ACI

  • 8 serialized stages
  • Final filter stage
  • Base with metal hose barb
  • 3-piece spring set
  • Silicone O-ring seals
  • Dual o-ring style inlet cone
  • Stainless steel collection plate set (6 Solid & 2 with Open-Centre)
  • Operator manual and complete mensuration certificate report.
  • Material options: Aluminium, Stainless Steel or Titanium

DPI Application

Dry Powder Inhaler (DPI) testing requires an added high capacity preseparator or pre-collector between the induction port and stage 0 for preventing upper stage mass overloading and is necessary to achieve the specified pressure drop through the device; this feature traps non-inhalable aerosols. To achieve the proper pressure drop of 4 kPa (40.8 cm water) in the inhaler, a higher vacuum flow rate at 60 or 90 L/minute may be needed. Higher flow rate application kits include additional stages for maintaining traditional cut point ranges with minimal setup effort. All DPI application options work together to achieve quality analytical results.

MDI Application

Metered Dose Inhaler (MDI) testing uses the standard ACI with induction port and is usually operated at a volumetric flow rate of 28.3 L/min, 60 and 90 L/min versions of the ACI are also available. The induction port also ensures that any portion of the aerosol moving too fast to enter the lungs in vivo is excluded from the impactor and in-vitro analysis.