Recent product-specific pharmacopeial monographs intended to assist developers of inhaled generic drugs call for the use of test equipment not specified in the USP/Ph. Eur. chapters on orally inhaled products.
In this Q&A, Copley Scientific Sales Director Mark Copley answers questions about the equipment and methods recommended for testing of fluticasone propionate (FP) and other popular inhaled generic targets.
Q: What is in the new FP-specific USP monographs?
A: The two new USP 36 Second Supplement monographs for the testing of FP were released in Dec 2013. One relates to the use of FP as an inhalation powder for delivery by a dry powder inhaler (DPI). The other is for FP delivered as an aerosol via metered dose inhaler (MDI).
The monographs cover both delivered dose uniformity (DDU) testing and aerodynamic particle size distribution (APSD) measurement. Delivered dose and APSD are required performance metrics for all orally inhaled products (OIPs) because of their defining influence on the success and consistency of drug delivery.
Glass sample collection apparatus for FP testing
Q: What special equipment is called for in the FP-specific monographs?
A: Specified equipment unique to the testing of FP includes:
• Glass sample collection apparatus for DDU testing of inhalation aerosols
• Glass sample collection apparatus for DDU testing of inhalation powders
• Modified induction port to be used with the Andersen Cascade Impactor (ACI) for APSD measurements
• Modified version of the ACI preseparator (for inhalation powder testing)
• Modified version of the ACI inlet cone (for inhalation aerosol testing).
The inlet geometry of the modified induction port is similar to that of the glass twin impinger, except that it is manufactured from either aluminum or 316 stainless steel. The similarity in geometry allows for the use of mouthpiece adapters designed for the glass twin impingers.
The modified induction port also features a tapered exit with no O-ring, which is why modified versions of the ACI preseparator and inlet cone are required in order for the ACI to accommodate the induction port.
