Novel pMDI formulations for pulmonary delivery of proteins

Hao-Ying Li, Peter C. Seville*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In this paper, we demonstrate that co-spray-drying a model protein with sodium carboxymethylcellulose (NaCMC) protects protein integrity during spray-drying, and that the resultant spray-dried powders can be successfully dispersed in hydrofluoroalkane (HFA) propellant to prepare pressurised metered dose (pMDI) formulations that exhibit high respirable fractions. The spray-dried powders were formulated as HFA-134a pMDI suspensions in the absence of any other excipients (e.g. surfactants) or co-solvents (e.g. ethanol). The in vitro aerosolisation profile of these systems was assessed using the twin stage impinger; fine particle fractions (FPF) ≥50% of the recovered dose were obtained. Following storage for five months, the aerosolisation performance was reassessed; the NaCMC-free formulation demonstrated a significant decrease in FPF, whereas the performance of the NaCMC-modified formulations was statistically equivalent to their initial performance. Thus, formulation of pMDI suspensions using NaCMC-based spray-dried powders is a promising approach for the pulmonary delivery of proteins and peptides.

Original languageEnglish
Pages (from-to)73-78
Number of pages6
JournalInternational Journal of Pharmaceutics
Issue number1-2
Early online date23 Oct 2009
Publication statusPublished - 29 Jan 2010


  • HFA-134a
  • pMDI
  • protein
  • sodium carboxymethylcellulose
  • spray-drying


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