Preparation of New Glycerol-Based Dendrimers and Studies on Their Behavior toward Essential Oil Encapsulation

Two new families of glycerol-based dendrimers(glyceroladendrimers (GADs) and glyceroclickdendrimers (GCDs))have been synthesized. Three generations have been isolated for eachfamily with good yields and were fully analyzed. The encapsulation ofessential oils (citronella and cinnamon) in GADs, GCDs, and also inpreviously described glycerodendrimers GD-PAMAMs and GD-PPIshas been studied by dynamic-headspace gas chromatography coupledto mass spectrometry. The retention rates obtained were from −35.8to 26.65% for citronella essential oil and from 2.14 to 38.84% for thecinnamon essential oil. In addition, the best results were obtained withGD-PAMAMs and GD-PPIs of higher generation. The interactionstudy between essential oils or more precisely their major componentshave been performed through NMR spectroscopy (1H NMR andDOSY NMR). No direct interactions between dendrimers andessential oils have been observed, but a surprising behavior of compression of the dendrimer in stable emulsions was observed.Indeed, the hydrodynamic radius of GD-PPI-3 has been reduced in the presence of cinnamon essential oil.