The crystal structures of Ti-4(III)[Si2O(PO4)(6)] ( P3 , Z = 3, a = 14.733(1), c = 7.363(1) & Aring;, R1 = 0.040, wR2 = 0.098, 7649 ind. refl., 170 variables), (Fe0.79Ti2.42Ti0.79IV)-Ti-II-Ti-III[Si2O(PO4)(6)] ( P3 , Z = 3, a = 14.6534(2), c = 7.3829(1) & Aring;, R1 = 0.036, wR2 = 0.088, 4026 ind. refl., 171 variables), and (Ti2Ti6IV)-Ti-III(PO4)(6)[Si2O(PO4)(6)] ( R3 , Z = 1, a = 8.446(2), c = 44.21(2) & Aring;, R1 = 0.047, wR2 = 0.120, 1373 ind. refl., 109 variables) have been refined from single-crystal data. The structures show hexagonal closest packing of phosphate groups with metal cations and [Si2O] groups occupying octahedral voids [square(PO4)(6)]. The close relationship of these and other silicophosphate structures to the NiAs and beta-Fe-2(SO4)(3) (see also NaZr2(PO4)(3) "NASICON") structure types is rationalized by group/subgroup considerations. This symmetry approach shows that systematic twinning is highly likely in silicophosphates, thus possibly leading to faulty crystal structure refinements. Our investigation strongly suggests that the proper composition of silicophosphates "(M3P5SiO19)-P-III" (M = Cr, V, Fe, Mo) reported in literature is actually M-4(III)-[Si2O(PO4)(6)]. In the mixed-valent compounds oxidation states were assigned to the cation sites by comparison to Ti2O3, TiP2O7 and FeTiO3. The powder reflectance spectrum of dark-blue (Fe0.79Ti2.42Ti0.79IV)-Ti-II-Ti-III[Si2O(PO4)(6)] shows a strong IVCT transition at nu = 17,500 cm(-1), and magnetic susceptibility data agree very well with the proposed oxidation states.

The goal of this study was to develop bioadhesive food protein nanoparticles using zein (Z), a hydrophobic corn protein, as the core and whey protein (WP) as the shell for oral pediatric drug delivery applications. Lopinavir (LPV), an antiretroviral drug, and fenretinide, an investigational anticancer agent, were used as model drugs in the study. The particle size of ZWP nanoparticles was in the range of 200-250 nm, and the drug encapsulation efficiency was >70%. The nanoparticles showed sustained drug release in simulated gastrointestinal fluids. ZWP nanoparticles enhanced the permeability of LPV and fenretinide across Caco-2 cell monolayers. In both ex vivo and in vivo studies, ZWP nanoparticles were found to be strongly bioadhesive. ZWP nanoparticles enhanced the oral bioavailability of LPV and fenretinide by 4 and 7-fold, respectively. ZWP nanoparticles also significantly increased the half-life of both drugs. The nanoparticles did not show any immunogenicity in mice. Overall, the study demonstrates the feasibility of developing safe and effective food protein-based nanoparticles for pediatric oral drug delivery.