Nonhalogenated solvent-based solvent evaporation process useful in preparation of PLGA microspheres

Jeeyoung Jang, Hongkee Sah

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The objective of this study was to develop an isopropyl formate-based evaporation process useful in producing poly-D,L-lactide-co-glycolide microspheres. Surprisingly, the evaporating tendency of isopropyl formate was comparable to that of methylene chloride and far better than that of ethyl acetate. After optimization of the isopropyl formate-based process, progesterone was encapsulated into microspheres. Under our conditions, its encapsulation efficiency ranged from 75.1% to 92.6%. Even though all microspheres took spherical geometry, their external and internal morphologies were greatly influenced by progesterone payloads. A GC analysis demonstrated that residual isopropyl formate in various microspheres was 1.8% to 4.0%. Interestingly, progesterone underwent polymorphic transition during the microencapsulation process the β form was present in microspheres with lower progesterone payloads, whereas the α form predominated over the β one at higher progesterone loads. In terms of human safety and environmental toxicity, isopropyl formate might have an edge over halogenated organic solvents for solvent evaporation.

Original languageEnglish
Pages (from-to)490-498
Number of pages9
JournalJournal of Microencapsulation
Issue number6
StatePublished - Sep 2011

Bibliographical note

Funding Information:
This study was supported by a grant from the Korean Health Technology R&D Project, Ministry for Health, Welfare and Family Affairs, Republic of Korea (A092018).


  • Microencapsulation
  • Microsphere
  • Solvent evaporation
  • Solvent extraction


Dive into the research topics of 'Nonhalogenated solvent-based solvent evaporation process useful in preparation of PLGA microspheres'. Together they form a unique fingerprint.

Cite this