Agglomerate properties and dispersibility changes of salmeterol xinafoate from powders for inhalation after storage at high relative humidity

Shyamal Chandra Das, Paul M Young, Ian Clair Larson, Peter James Stewart

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15 Citations (Scopus)


This study investigated changes in agglomeration and the mechanism of dispersibility decrease of salmeterol xinafoate (SX) from SX-lactose mixtures for inhalation after storage at 75 RH for 3 months. The dispersibility, PSD and in situ PSD of aerosol plumes of SX alone and SX-coarse lactose (CL) mixtures containing 0, 5, 10 and 20 micronized lactose (ML) before and after storage were determined by a Next Generation Impactor (NGI), a Mastersizer 2000 and a Spraytec, respectively. The PSD of ML increased after storage at 75 RH, but dispersibility of SX using the stored ML increased. After storage, the SX of the mixture containing 20 ML (M20F) significantly increased (P>0.05) in the throat and mouthpiece, preseparator and stage 1 of NGI, while it significantly decreased in the remaining stages (P>0.05). In situ analysis of aerosol plumes of M20F supported this result with an increased presence of particles of 4-25 -m and a decreased respirable particle distribution of
Original languageEnglish
Pages (from-to)442 - 450
Number of pages9
JournalEuropean Journal of Pharmaceutical Sciences
Issue number3-4
Publication statusPublished - 2009

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