Aerosol Particle Size Characterization

Service offered by: Medicated Aerosol Consultant

The USP and the British pharmacopeia stated that, for dosage forms prepared to be given to patients as oral or nasal aerosol delivery, the aerodynamic size characterization must be determined (mass median aerodynamic diameter (MMAD), Fine particle dose (FPD), Fine particle fraction of emitted dose and of nominal dose (FPF), geometrical standard deviation (GSD), Calculated delivered dose (TED)).

The Anderson Cascade Impactor consists of a stack of eight plates, each containing a series of precision drilled holes, and a final filter stage. The diameter of the holes decreases progressively in each succeeding stage. Therefore, the jet velocity increases as a particle travels through the impactor. The Anderson Cascade Impactor operates at a flow of 28.3 L/min mostly for metered dose inhaler. This method allows a more detailed description of the particle size distribution than either the MSLI or the Twin Impinger. Anderson Cascade Impactor is designed to determine the aerodynamic size characterization for suspension, solution and emulsion dosage forms prepared for inhalation (at inhalation flows of 15 L/min), metered dose inhaler (at inhalation flows of 28.3 L/min) and dry powder dosage form prepared for inhalation (high flows 60 and 90 L/min).

Applications and uses

• Prediction of drug amount deposited in different parts of the lung without an in vivo study.
• Essential for bioequivalence comparison between generics and originators

Device details

Anderson Cascade Impactor; Copley Scientific Ltd, Nottingham, UK.

Technical terms

• Sample types: Dosage form for inhalation e.g. solution, suspension and emulsion dosage form for nebulization, dry powder dosage form for inhalation and metered dose inhaler with and without spacer.
• Minimum quantity: for each run, we need 2 ml nebulizer solution for nebulized dosage forms, three filled size 3 capsules for dry powder inhalations, or a filled metered dose inhaler with and without different spacers.
• You are required to submit an HPLC method for analysis of your target drug.
• Estimated time of the experiment is 10 days.
• Work includes running your sample through the cascade impactor followed by HPLC analysis of your target drug in each phase (~15 HPLC runs)