Shear-Thinning Viscous Materials for Subconjunctival Injection of Microparticles

Shiyu Xia, Zheng Ding, Lixia Luo, Baiwei Chen, Joanna Schneider, Jin Yang, Charles G. Eberhart, Walter J. Stark, Qingguo Xu

Research output: Contribution to journalArticlepeer-review


While drug-loaded microparticles (MPs) can serve as drug reservoirs for sustained drug release and therapeutic effects, needle clogging by MPs poses a challenge for ocular drug delivery via injection. Two polymers commonly used in ophthalmic procedures—hyaluronic acid (HA) and methylcellulose (MC)—have been tested for their applicability for ocular injections. HA and MC were physically blended with sunitinib malate (SUN)–loaded PLGA MPs for subconjunctival (SCT) injection into rat eyes. The HA and MC viscous solutions facilitated injection through fine-gauged needles due to their shear-thinning properties as shown by rheological characterizations. The diffusion barrier presented by HA and MC reduced burst drug release and extended overall release from MPs. The significant level of MP retention in the conjunctiva tissue post-operation confirmed the minimal leakage of MPs following injection. The safety of HA and MC for ocular applications was demonstrated histologically.

Original languageEnglish (US)
Article number8
JournalAAPS PharmSciTech
Issue number1
StatePublished - Jan 2021


  • hyaluronic acid
  • methylcellulose
  • microparticles
  • ocular drug delivery
  • shear-thinning materials

ASJC Scopus subject areas

  • Pharmaceutical Science


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