Protein encapsulation in and release from monodisperse double-wall polymer microspheres

Yujie Xia, Qingxing Xu, Chi Hwa Wang, Daniel W. Pack

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Biodegradable polymer double-wall microspheres (DWMS) are promising vehicles for macromolecular therapeutics such as proteins and peptides. Using precision particle fabrication (PPF) technology, uniform DWMS with outer diameter approximately 55 μm were fabricated comprising poly(lactide-co-glycolide) cores encapsulating bovine serum albumin (BSA) and approximately 10 μm thick, drug-free, poly(lactic acid) (PLA) shells of varying PLA molecular weight. Also, monolithic single-wall microspheres (SWMS) were fabricated to mimic the BSA-loaded core. The use of relatively fast-extracting ethyl acetate and slowly extracting dichloromethane as shell- and core-phase solvents, respectively, was found to produce DWMS with well-defined core-shell structure, high BSA encapsulation efficiency, and the desired localization of protein in the particle core. Initial protein distribution, particle erosion, and in vitro protein release from DWMS and SWMS were examined. The presence of a BSA-free shell in DWMS decreased the protein release rate and extended the duration of release from approximately 50 days to 70-80 days, demonstrating the capacity of such DWMS to provide enhanced control of protein delivery rates.

Original languageEnglish
Pages (from-to)1601-1609
Number of pages9
JournalJournal of Pharmaceutical Sciences
Issue number5
StatePublished - May 2013

Bibliographical note

Funding Information:
This work was supported by the National Institute of Health Grant EB005181 and GM085222. Scanning electron micrographs were obtained in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois. Confocal microscopy measurements were obtained in the Beckman Institute Imaging Technology Group at University of Illinois.


  • Bovine serum albumin
  • Controlled release
  • Microspheres
  • PLGA
  • Poly(lactic acid)
  • Protein delivery

ASJC Scopus subject areas

  • Pharmaceutical Science


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