W/O microemulsions as dendrimer nanocarriers: An epr study

Shifra Rokach, Maria Francesca Ottaviani, Alexander I. Shames, Ido Nir, Abraham Aserin, Nissim Garti

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


A complex system, based on a dendrimer solubilized in the aqueous core of water-in-oil microemulsion, may combine the advantages of both dendrimers and microemulsions to provide better control of drug release. We report for the first time the use of EPR technique to determine the effect of solubilized dendrimer on the structure of the microemulsion. The solubilized poly(propyleneimine) (PPI-G2) interacts with sodium bis(2-ethylhexyl) sulfosuccinate (AOT). EPR analysis provided information on polarity, microviscosity, and molecular order of the systems. Polarity and microviscosity increased from unloaded water-in-oil microemulsion to the system loaded with 0.2 wt % PPI-G2, but remained unchanged with higher PPI-G2 loads. The degree of order also increased with 0.2 wt % PPI-G2 with only minor additional increase with larger quantities (25 wt %) of PPI-G2. Variations in pH only slightly affected the structure of microemulsion in the absence and presence of the loaded dendrimers. Aliphatic oils with longer lipophilic chains enhanced the structural order of the microemulsion. On increasing water content, polarity and degree of order increased. PPI-G2 dendrimer in small loads is attracted by the negatively charged AOT and thus intercalates in the interface of the droplets. Yet, at higher PPI-G2 loads, the excess molecules are solubilized in the water core.

Original languageEnglish
Pages (from-to)12633-12640
Number of pages8
JournalJournal of Physical Chemistry B
Issue number41
StatePublished - 18 Oct 2012

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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