Nephele Mixing Inlet

The aerodynamic particle size distribution (APSD) of inhaled drug products may depend on the inhalation flow rate versus time profile used by a patient. The patented Nephele Mixing Inlets (all covered by US Patent 6,435,004 and licensed to RDD Online) allow use of cascade impactors to establish the APSD following inhaler actuation according to simulated inhalation flow profiles based on patients. The mixing inlet enables internationally harmonized and calibrated cascade impactors, such as the Andersen Cascade Impactor (ACI) and Next Generation Impactor (NGI) that are recognized by regulators worldwide, to be adapted to sample the output of an inhaler under realistic flow conditions. When aerosols from inhalation devices are sampled through inlet ports with realistic "throat geometries", the technique enables investigators to compare the APSD of aerosols that penetrate the throat (and thus enter the lung) under various flow conditions likely to be used by patients.

All Nephele Mixing Inlets gently merge, with virtually no turbulence (and minimal aerosol losses) a particle-free sheath air stream with a second central air stream containing an aerosol. A Nephele Mixing Inlet mounted between the aerosol entry port (e.g. the USP Induction Port) and the inlet to the cascade impactor allows the impactor to be operated at a constant flow rate (e.g. 60 LPM) while allowing a lower fixed or variable flow rate to draw aerosol from the inhaler device and entry port. A typical experimental set-up is shown below.

Experimental Set Up for Breath Profile Simulator – Nephele Mixing Inlet.
Adapted from Olsson et al, Respiratory Drug Delivery 2010, pp 225-234.
  • The Nephele Mixing Inlet fits between the USP Induction Port (or other realistic throat geometry model) and the inlet of a cascade impactor
  • Supplemental, particle-free air must be provided from a customer supplied compressed air source connected to the side hose barb of the mixing inlet.
  • The original Nephele Mixing Inlet (only available via special order) required an adaptor to be used with some cascade impactors. New designs are now available for direct attachment to both the Andersen Cascade Impactor (Nephele II Mixing Inlet) and the Next Generation Impactor (Nephele III Mixing Inlet).
  • All Nephele Mixing Inlets have a unique serial number to enable traceability.

The Nephele Mixing Inlet has been described in the following studies:

Mixing Inlet Options

  • NMI I: Original Nephele Mixing Inlet (Only available by special order)
  • NMI II: Nephele II Mixing Inlet for Andersen Cascade Impactor
  • NMI III: Nephele III Mixing Inlet for Next Generation Impactor


  • NMI 001: Replacement seals for Original Nephele Mixing Inlet
  • NMI 002: Replacement seals for Nephele II Mixing Inlet
  • NMI 003: Replacement seals for Nephele III Mixing Inlet

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