Localization and reactivity of a hydrophobic solute in lecithin and caseinate stabilized solid lipid nanoparticles and nanoemulsions.
The distribution and reactivity of the lipophilic spin probe 4-phenyl-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl nitroxide (PTMIO) in tetradecane (C14)- and eicosane (C20)-in-water emulsions and solid lipid nanoparticles (SLN) respectively, were investigated by electron paramagnetic resonance (EPR) spectroscopy. The lipid phase (10 wt% C14 or C20) was emulsified into either caseinate solutions (1 wt%) or lecithin+bile salt dispersions (2.4 wt%+0.6 wt%) at 70-75 °C. In C14 emulsions stabilized with lecithin+bile salt, three populations of PTMIO were observed: a population in the lipid phase (~60%, a(N)~13.9 G), an aqueous phase population (~20%, a(N)~15.4 G) with high mobility, and an immobilized surface layer population (~20%, a(N)~14.2 G) with low mobility. However, in C14 emulsions stabilized by caseinate, only two distinct populations of PTMIO were seen: a lipid phase population (~70%, a(N)~13.8 G) and an aqueous phase population (~30%, a(N)~15.5 G) with high mobility. In C20 SLN stabilized with either lecithin+bile salt or caseinate, PTMIO was excluded from the lipid phase. In lecithin+bile salt-stabilized C20 SLN, the majority of the probe (~77%) was in the interfacial layer. For both surfactant systems the rate of PTMIO reduction by aqueous iron/ascorbate was greater for C20 SLN than C14 emulsions. Lecithin affects the properties of emulsions and SLN as delivery systems by providing a distinct environment for small molecules.
Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
Umut
U
Yucel
Ryan J
RJ
Elias
John N
JN
Coupland
D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D004655:Emulsions / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D054709:Lecithins / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry
D002364:Caseins; D004655:Emulsions; D054709:Lecithins; D008055:Lipids; D013501:Surface-Active Agents