Controlled and Extended Release of a Model Protein from a Microsphere-Hydrogel Drug Delivery System

Christian R. Osswald, Jennifer J. Kang-Mieler

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

In extended ocular drug delivery applications, it is necessary to exert control over the release characteristics of the drug. Design considerations must be made to limit the initial burst (IB) and ensure complete release of drug from the drug delivery system (DDS). In this study, ovalbumin was used as a model protein to explore the effects on release of polymer formulation and fabrication technique in poly(lactic-co-glycolic acid) (PLGA) microspheres. Furthermore, the effect on release of suspending these microspheres in an injectable, thermo-responsive poly(N-isopropylacrylamide)-based hydrogel was determined. To characterize release, ovalbumin was radiolabeled with iodine-125. Regardless of polymer formulation or fabrication technique, pulsatile release was achieved with a second burst occurring after ~70 days for microspheres alone. Suspending PLGA 75:25 microspheres within hydrogel reduced the IB by ~75%, delayed the second burst by 28 days, and extended release out to ~200 days with steadier, consistent release throughout compared to microspheres alone. The combined microsphere-hydrogel DDS remains injectable through small-gauge needles and may have many applications, namely ocular drug delivery to the posterior segment.

Original languageEnglish
Pages (from-to)2609-2617
Number of pages9
JournalAnnals of Biomedical Engineering
Volume43
Issue number11
DOIs
StatePublished - 1 Nov 2015

Keywords

  • Hydrogel
  • Microspheres
  • Ocular drug delivery
  • Ovalbumin
  • Poly(N-isopropylacrylamide)
  • Poly(lactic-co-glycolic acid)

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