Influence of PEI as a core modifying agent on PLGA microspheres of PGE₁, a pulmonary selective vasodilator

Int J Pharm. 2011 Jul 15;413(1-2):51-62. doi: 10.1016/j.ijpharm.2011.04.017. Epub 2011 Apr 16.


This study tests the hypothesis that large porous poly (lactic-co-glycolic acid) (PLGA) microparticles modified with polyethyleneimine (PEI) are viable carriers for pulmonary delivery of prostaglandin E(1) (PGE(1)) used in the treatment of pulmonary arterial hypertension (PAH), a pulmonary vascular disorder. The particles were prepared by a double-emulsion solvent evaporation method with PEI-25 kDa in the internal aqueous phase to produce an osmotic pressure gradient. Polyvinyl alcohol (PVA) was used for external coating of the particles. The particles were examined for morphology, size, aerodynamic diameter, surface area, pore volume and in-vitro release profiles. Particles with optimal properties for inhalation were tested for in-vivo pulmonary absorption, metabolic stability in rat lung homogenates, and acute toxicity in rat bronchoalveolar lavage fluid and respiratory epithelial cells, Calu-3. The micromeritic data indicated that the PEI-modified particles of PGE(1) are optimal for inhalation. Incorporation of PEI in the formulations resulted in an increased entrapment efficiency - 83.26 ± 3.04% for particles with 1% PVA and 95.48 ± 0.46% for particles with 2% PVA. The amount of cumulative drug released into the simulated interstitial lung fluid was between 50.8 ± 0.76% and 55.36 ± 0.06%. A remarkable extension of the circulation half-life up to 6.0-6.5h was observed when the formulations were administered via the lungs. The metabolic stability and toxicity studies showed that the optimized formulations were stable at physiological conditions and relatively safe to the lungs and respiratory epithelium. Overall, this study demonstrates that large porous inhalable polymeric microparticles can be a feasible option for non-invasive and controlled release of PGE(1) for treatment of PAH.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, N.I.H., Extramural

MeSH terms

  • Administration, Inhalation
  • Alprostadil / adverse effects
  • Alprostadil / chemistry*
  • Alprostadil / pharmacokinetics
  • Alprostadil / pharmacology
  • Animals
  • Bronchoalveolar Lavage Fluid
  • Cell Survival / drug effects
  • Delayed-Action Preparations
  • Drug Carriers
  • Drug Compounding
  • Excipients / adverse effects
  • Excipients / chemistry*
  • Excipients / metabolism
  • Extracellular Fluid / drug effects
  • Lactic Acid / adverse effects
  • Lactic Acid / chemistry*
  • Lactic Acid / metabolism
  • Lung / drug effects*
  • Male
  • Microspheres
  • Particle Size
  • Polyethyleneimine / adverse effects
  • Polyethyleneimine / chemistry*
  • Polyethyleneimine / metabolism
  • Polyglycolic Acid / adverse effects
  • Polyglycolic Acid / chemistry*
  • Polyglycolic Acid / metabolism
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyvinyl Alcohol / adverse effects
  • Polyvinyl Alcohol / chemistry
  • Polyvinyl Alcohol / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Surface Properties
  • Vasodilator Agents / adverse effects
  • Vasodilator Agents / chemistry*
  • Vasodilator Agents / pharmacokinetics
  • Vasodilator Agents / pharmacology


  • Delayed-Action Preparations
  • Drug Carriers
  • Excipients
  • Vasodilator Agents
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyglycolic Acid
  • Lactic Acid
  • Polyvinyl Alcohol
  • Polyethyleneimine
  • Alprostadil