Structural characteristics of mPEG-PDLLA and their effects on micelle stability

  • Bumchan MinEmail author
  • Minhyo Seo
  • Bong Oh Kim
  • Youngjoo Koh
  • Yilwoong Yi
  • Hyerim Kim
Short Communication


The correlation between polymer microstructure of mPEG-PDLLA and secondary aggregation of its micelle was studied. Close examination of 1H NMR spectra revealed that the methine moieties, -CH(CH3)-, of mPEG-PDLLA polymer well represented its microstructure. To elucidate the physicochemical characteristics of various microstructures, we have developed an index, called L-ratio, to indicate the relative content of heterotactic component within the polymer. Storage stability of micelles from six polymers with different L-ratios (L-ratio ranging from 28 to 33%) was studied at 30 °C and 50 °C, and changes in average particle size were monitored to evaluate their secondary aggregation. We have found that polymers with high L-ratio takes longer time to secondary aggregation of polymeric micelles to occur. The findings should provide insightful guidance in the development of polymeric micelles.


Polymeric micelle Block copolymer mPEG-PDLLA Polymer microstructure Stability Secondary aggregation 



The authors thank Dr. Joonyoung Park for his discussion and proofreading during revision of the manuscript.

Funding information

This study was supported by R&D fund of Samyang Biopharmaceutical Corporation and Grant 10047811 from Ministry of Trade, Industry and Energy (MOTIE, South Korea).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Bumchan Min
    • 1
    Email author
  • Minhyo Seo
    • 1
  • Bong Oh Kim
    • 1
  • Youngjoo Koh
    • 1
  • Yilwoong Yi
    • 1
  • Hyerim Kim
    • 1
  1. 1.Samyang Biopharmaceuticals CorpSeongnam-siSouth Korea

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