title: Conception, preparation and properties of functional carrier particles for pulmonary drug delivery.
abstract: BACKGROUND
  The effectiveness of aerosol therapy is significantly reduced by the mucus layer covering the airways of the tracheobronchial tree. According to the present concept, drug particles are delivered to the lung together with the functional carrier particle that facilitates both the drug transport into the lungs and the penetration of deposited particles through the mucus. The approach of manufacturing multi-component powders with mucoactive compounds and anti-asthmatic medicines (DSCG) bound together in a single particle is additionally considered.
  
  
  METHODS
  Powders were produced with the spray-drying technique from aqueous precursor solutions containing pure low molecular weight dextran, pure mannitol and dextran/mannitol-N-acetyl cysteine (NAC) mixtures (4:1 and 1:1). NAC has been selected for this purpose as a compound, which is known to be mucolytic. Dextran and mannitol are potentially applicable in the field of inhalation drug delivery. They have been used as stabilizers of functional carrier particles. Powders were characterized for their yield and physicochemical properties including: morphology (SEM), moisture content and thermal properties (DSC). Aerosol performance was determined with NGI impactor after standardized aerosolization of the produced powders in a commercial DPI.
  
  
  RESULTS
  Particle size distributions of dextran-NAC powders were characterized by high fine particle fraction (45-62%), which assures good particle deposition in the lower airways. The thermodynamic properties of the powders based on the temperature of the glass transition T(g) (50-63 °C) suggest the required stability during storage at moderate humidity.
  
  
  CONCLUSIONS
  Preliminary examination of the required properties of these particles confirms their potential as functional carriers for pulmonary drug delivery.
authors.affiliation: Faculty of Chemical and Process Engineering, Warsaw University of Technology, 1 Waryńskiego Street, 00-645 Warsaw, Poland. M.Odziomek@ichip.pw.edu.pl
authors.forename: Marcin
authors.initials: M
authors.lastname: Odziomek
authors.forename: Tomasz R
authors.initials: TR
authors.lastname: Sosnowski
authors.forename: Leon
authors.initials: L
authors.lastname: Gradoń
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D000280:Administration, Inhalation; D000336:Aerosols; D003911:Dextrans / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems; D004355:Drug Stability; D004356:Drug Storage; D058995:Dry Powder Inhalers; D005100:Expectorants / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D006813:Humidity; D008353:Mannitol / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D044367:Phase Transition; D011208:Powders; D013696:Temperature; D013816:Thermodynamics; D014018:Tissue Distribution
chemical_list: D000336:Aerosols; D003911:Dextrans; D004337:Drug Carriers; D005100:Expectorants; D011208:Powders; D008353:Mannitol; D000111:Acetylcysteine