Sunitinib microspheres based on [PDLLA-PEG-PDLLA]-b-PLLA multi-block copolymers for ocular drug delivery

F. Ramazani*, C. Hiemstra, R. Steendam, F. Kazazi-Hyseni, C.F. van Nostrum, G. Storm, F. Kiessling, T. Lammers, W.E. Hennink, R.J. Kok

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

38 Citations (Scopus)
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Sunitinib is a multi-targeted receptor tyrosine kinase (RTK) inhibitor that blocks several angiogenesis related pathways. The aim of this study was to develop sunitinib-loaded polymeric microspheres that can be used as intravitreal formulation for the treatment of ocular diseases. A series of novel multi-block copolymers composed of amorphous blocks of poly-(d,l-lactide) (PDLLA) and polyethylene glycol (PEG) and of semi-crystalline poly-(l-lactide) (PLLA) blocks were synthesized. Sunitinib-loaded microspheres were prepared by a single emulsion method using dichloromethane as volatile solvent and DMSO as co-solvent. SEM images showed that the prepared microspheres (∼30 μm) were spherical with a non-porous surface. Sunitinib-loaded microspheres were studied for their degradation and in-vitro release behavior. It was found that increasing the percentage of amorphous soft blocks from 10% to 30% accelerated the degradation of the multi-block copolymers. Sunitinib microspheres released their cargo for a period of at least 210 days by a combination of diffusion and polymer erosion. The initial burst (release in 24 h) and release rate could be tailored by controlling the PEG-content of the multi-block copolymers. Sunitinib-loaded microspheres suppressed angiogenesis in a chicken chorioallantoic membrane (CAM) assay. These microspheres therefore hold promise for long-term suppression of ocular neovascularization.

Original languageEnglish
Pages (from-to)368-377
Number of pages10
JournalEuropean journal of pharmaceutics and biopharmaceutics
Issue numberPart B
Publication statusPublished - 1 Sept 2015


  • Angiogenesis
  • Microspheres
  • Multi-block copolymers
  • Ocular drug delivery
  • Release and degradation
  • Single emulsion (O/W)
  • Sunitinib malate
  • Thermal analysis
  • 2023 OA procedure


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