Preparation and characterization of drug-loaded polymethacrylate microspheres by an emulsion solvent evaporation method

B. K. Kim, S. J. Hwang, J. B. Park, H. J. Park

Research output: Contribution to journalReview articlepeer-review

119 Citations (Scopus)


Microspheres containing the anti-hypertension drug, felodipine, were prepared by the emulsion solvent evaporation method (o/o) using acrylate methacrylate copolymers, Eudragit RL PO and Eudragit RS PO, as wall materials. In order to increase the encapsulation efficiency, a mixed solvent system comprising 1:1 proportions of acetonitrile and dichloromethane was used as a dispersed phase. The morphology of the microspheres was evaluated using a scanning electron microscope, which showed a spherical shape with smooth surface. The mean sphere diameter was between 9.5-13.2 μm and the microencapsulation efficiencies ranged from 51.4-80.4%. The release profiles and encapsulation efficiencies depended strongly on the structure of the polymers used as wall materials. The release rate of the Eudragit RS PO microspheres was much lower than that of Eudragit RL PO microspheres. Whereas Eudragit RL PO microspheres followed the Higuchi rule, Eudragit RS PO microspheres exhibited a triphasic release profile. It is concluded that drug release rate can be controlled by choice of polymer type.

Original languageEnglish
Pages (from-to)811-822
Number of pages12
JournalJournal of Microencapsulation
Issue number6
Publication statusPublished - 2002 Nov

Bibliographical note

Funding Information:
This study was supported by a grant of the Korea Health 21 R&D Project, Minitrsy of Health & Welfare, Republic of Korea (HMP-00-PT-21700-0017. )


  • Emulsion solvent evaporation
  • Eudragit
  • Felodipine
  • Microspheres
  • Mixed solvent system

ASJC Scopus subject areas

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


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