Polymer Bulletin

, Volume 66, Issue 8, pp 1063–1073 | Cite as

The effect of aliphatic esters on the formation and degradation behavior of PLGA-based in situ forming system

  • A. MashakEmail author
  • H. Mobedi
  • F. Ziaee
  • M. Nekoomanesh
Original Paper


The purpose of this study was to investigate the effect of three aliphatic esters, ethyl heptanoate, methyl heptanoate, and ethyl nonanoate on the in vitro degradation behavior of in situ forming systems. In situ forming implants based on 33% (w/w) poly (lactide-co-glycolide) (PLGA)/57% (w/w) N-methyl-2-pyrrolidone (NMP)/10% (w/w) esters were prepared after injection of the final formulation in phosphate buffer solution (pH 7.4, 0.2 M) at 37 °C. The influence of additives on the implants formation, morphology, and also on their in vitro degradation behaviors over a period of 45 days was investigated. The degraded matrices were evaluated to determine morphological analysis by SEM and 1H-NMR study. The solution of degradation medium was studied to indicate NMP removal and altering acidity. The results showed that the additives generated a high porous structure and caused the fast phase inversion. However, the 1H-NMR spectra indicated that ester additives remained in the matrices during degradation periods. The results of the acidity study showed that the degradation rates in the matrices containing esters were higher than the control matrix. In addition, it is shown that esters with lower molecular weight have affected the polymer degradation more efficiently than higher molecular weight esters.


In situ forming systems Biodegradation Solvent removal Morphology Poly (lactide-co-glcolide) Aliphatic esters 


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • A. Mashak
    • 1
    Email author
  • H. Mobedi
    • 1
  • F. Ziaee
    • 2
  • M. Nekoomanesh
    • 3
  1. 1.Department of Novel Drug Delivery SystemsIran Polymer and Petrochemical InstituteTehranIran
  2. 2.Department of Polymer Science and SynthesisIran Polymer and Petrochemical InstituteTehranIran
  3. 3.Department of EngineeringIran Polymer and Petrochemical InstituteTehranIran

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