AAPS PharmSciTech

, Volume 13, Issue 2, pp 707–712 | Cite as

Structure and Dissolution of l-Leucine-Coated Salbutamol Sulphate Aerosol Particles

  • Janne RaulaEmail author
  • Jukka Seppälä
  • Jari Malm
  • Maarit Karppinen
  • Esko I. Kauppinen
Research Article


l-Leucine formed different crystalline coatings on salbutamol sulphate aerosol particles depending on the saturation conditions of l-leucine. The work emphasizes a careful characterization of powders where structural compartments such as crystal size and particle coating may affect the performance of drug when administered. The sublimation of l-leucine from the aerosol particles took place 90°C lower temperature than the bulk l-leucine which was attributed to result from the sublimation of l-leucine from nano-sized crystalline domains. The dissolution slowed down and initial dissolution rate decreased with increasing l-leucine content. Decreasing crystalline domains to nano-scale improve heat and mass transfer which was observed as the lowered decomposition temperature of the drug salbutamol sulphate and the sublimation temperature of surface material l-leucine as well as the altered dissolution characteristics of the drug. The structure of the coated drug particles was studied by means of thermal analysis techniques (DSC and TG), and the dissolution of salbutamol sulphate was studied as an on-line measurement in a diffusion cell.


aerosol dissolution l-leucine coating nanocrystals sublimation 



We thank Academy of Finland (project nos. 133407 and 140362) for financial support.

Supplementary material

12249_2012_9789_MOESM1_ESM.docx (45 kb)
ESM 1 (DOCX 42 kb)


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Copyright information

© American Association of Pharmaceutical Scientists 2012

Authors and Affiliations

  • Janne Raula
    • 1
    Email author
  • Jukka Seppälä
    • 2
  • Jari Malm
    • 3
  • Maarit Karppinen
    • 3
  • Esko I. Kauppinen
    • 1
  1. 1.Department of Applied PhysicsAalto University School of ScienceEspooFinland
  2. 2.Department of Biotechnology and Chemical TechnologyAalto University School of Chemical TechnologyEspooFinland
  3. 3.Department of ChemistryAalto University School of Chemical TechnologyEspooFinland

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