title: Behavior of PPI-G2 Dendrimer in a Microemulsion.
abstract: Dendrimer nanostructures are of eminent interest in biomedical applications because of their uniform and well-defined molecular size and shape, and their ability to cross cell membranes and reduce the risk of premature clearance from the human body. Dendrimers perform as gene and drug carriers and have also shown significant therapeutic properties for treating cancer and neurodegenerative diseases. A complex drug delivery system, based on a dendrimer solubilized in the aqueous core of a water-in-oil (W/O) microemulsion (ME) along with the drug may combine the advantages of both dendrimers and MEs to provide better control of drug release. We propose a new microemulsion composed of drug-permitted surfactants and dendrimer that can be used as a potential controlled drug delivery nanosystem. The influence of second generation poly(propyleneimine) (PPI-G2) dendrimer; solubilized in (W/O) ME with a capacity of up to 25 wt% PPI-G2 at various pHs; and their interactions with the surfactant phosphatidylcholine (PC), cosurfactant (butanol), and water was studied. SAXS and EPR measurements indicated that increasing PPI-G2 concentration reduces droplet curvature and increases droplet size thus increasing macro-(SAXS) and micro-(EPR) order degree. Furthermore, SD-NMR and ATR-FTIR show stronger interactions between PPI-G2 and water molecules at the expense of PC and butanol headgroups hydration, which increases microviscosity (EPR). PPI-G2's effect is somewhat opposite to the increasing water phase effect, thus reducing the amount of free water (DSC) and slowing the mobility of all ME components (SD-NMR).
authors.affiliation: The Ratner Chair of Chemistry, Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel.|Judea Regional Research & Development Center , Carmel 9040400, Israel.
authors.forename: Shifra
authors.initials: S
authors.lastname: Rokach
authors.affiliation: Department of Earth, Life and Environment Sciences, University of Urbino , Loc. Crocicchia, Urbino 61029, Italy.
authors.forename: Maria Francesca
authors.identifier: 0000-0002-4681-4718
authors.initials: MF
authors.lastname: Ottaviani
authors.affiliation: Department of Physics, Ben-Gurion University of the Negev , P.O. Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Alexander I
authors.identifier: 0000-0002-0574-1911
authors.initials: AI
authors.lastname: Shames
authors.affiliation: The Ratner Chair of Chemistry, Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel.
authors.forename: Abraham
authors.initials: A
authors.lastname: Aserin
authors.affiliation: The Ratner Chair of Chemistry, Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel.
authors.forename: Nissim
authors.initials: N
authors.lastname: Garti