Encapsulation of PROLI/NO in biodegradable microparticles

H. S. Jeh, S. Lu, Steven George

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Biodegradable hydrophilic polymers poly-lactic-co-glycolic acid (PLGA) and polyethylene oxide-co-lactic acid (PELA) were used to encapsulate a small hydrophilic prodrug (PROLI/NO) as a strategy to deliver nitric oxide (NO) by inhalation. The microparticles were prepared using double emulsion and solvent evaporation, followed by freeze-drying. The NO release kinetics were characterized by three parameters: the maximum concentration of NO per unit weight of microparticles, Cmax (nM mg-1); the window of time for which the concentration exceeded 50% of Cmax W50 (min); and the initial rate of release, Ri (nM mg-1 min-1). PLGA-based microparticles did not encapsulate PROLI/NO. PELA-based microparticles demonstrated an entrapment efficiency rate of 43%, a mass median diameter of 2.3 μm, and NO release in a physiological buffer characterized by Cmax = 123, W50 = 4.11, and Ri = 78.7. Addition of gelatin as a hydrophilic binding moiety in the first emulsion allowed PLGA-based microparticles to encapsulate PROLI/NO; however, the mass median diameter was too large for inhalation (23.5 μm). It is concluded that the hydrophilic polyethylene glycol-moiety in PELA allows for efficient encapsulation of PROLI/NO, and PELA-based microparticles might be a strategy to generate a stable inhalable form of NO.

Original languageEnglish (US)
Pages (from-to)3-13
Number of pages11
JournalJournal of Microencapsulation
Issue number1
StatePublished - Feb 1 2004


  • Inhalation
  • Microsphere
  • Nitric oxide
  • PELA
  • PLGA
  • Pulmonary hypertension

ASJC Scopus subject areas

  • Bioengineering
  • Pharmaceutical Science
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Colloid and Surface Chemistry


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