Protein release kinetics of a biodegradable implant for fracture non-unions

C. M. Agrawal, J. Best, J. D. Heckman, B. D. Boyan

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


Non-union of long bone fractures is often a serious complication of fracture healing. It is estimated that 100000 non-unions occur in the United States annually and result in the loss of function of the involved limb. The present study was performed to develop a microporous polylactic acid-polyglycolic acid (PLA-PGA) implant for the delivery of bone morphogenetic protein (BMP) to sites of fracture non-unions, and to characterize the protein release kinetics of such an implant in vitro. A 50:50 copolymer of PLA-PGA was used to fabricate the implants using a gel formation technique. The implants were subjected to hydrolytic degradation in phosphate-buffered saline at 37 °C for up to 72 d. The protein release and the polymer degradation were monitored during this time period. The release kinetics of these implants were studied using a model protein, soybean trypsin inhibitor (TI), as well as BMP. The results indicate that there is a burst release of the proteins in the initial 48 h followed by a lower elution rate. The release of both the proteins followed similar trends. The molecular weight of the polymer decreased at a faster rate compared to its mass.

Original languageEnglish (US)
Pages (from-to)1255-1260
Number of pages6
Issue number16
StatePublished - 1995


  • Polylactic acid
  • degradation
  • fracture non-union
  • molecular weight
  • polyglycolic acid
  • protein release

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials


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