Xanthan and gum acacia modified olive oil based nanoemulsion as a controlled delivery vehicle for topical formulations.

In this study, olive oil nanoemulsion modified with xanthan gum and gum acacia was explored as a potential controlled topical delivery vehicle. Oil-in-water nanoemulsion formulated with optimized composition of olive oil, tween 80, and water was used as the drug carrier and further modified with gum. Effect of gum on nanoemulsion different physiochemical characteristics, stability, rheology, drug release and encapsulation efficiency were investigated. Results showed that developed nanoemulsion behaved as low viscosity Newtonian fluid and released 100 % drug within 6 h. Modification with xanthan and gum acacia had significantly improved formulation viscosity, drug encapsulation efficiency (>85 %) and controlled drug release up to 40 % with release pattern following Korsmeyer-Peppas model. Additionally, xanthan gum modified formulation exhibited shear thinning rheology by forming an extended network in the continuous phase, whereas gum acacia modified formulation behaved as Newtonian fluid at high shear rate (>200 s-1). Furthermore, xanthan gum modified formulations had improved zeta potential, stability, monodispersity, and hemocompatibility and showed high antibacterial activity against S. aureus than gum acacia modified formulations. These results indicate the higher potential of xanthan gum modified formulation as a topical delivery vehicle. Moreover, skin irritation test demonstrated the safety of developed formulations for topical application.

Halogen Bonding of Organoiodines and Triiodide Anions in (NMe3 Ph)+ Salts.

To study the role of the triiodide (I3 )- anion in establishing various halogen bonding patterns, the trimethylphenylammonium iodide (NMe3 PhI) salt was reacted with diiodine (I2 ) in the presence of a series of organoiodines, tetraiodoethylene (TIE), 1,2-diiodo-3,4,5,6-tetrafluorobenzene (o-F4 DIB), 1,4-diiodo-2,3,5,6-tetrafluorobenzene (p-F4 DIB), and 1,3,5-trifluoro-2,4,6-triiodobenzene (1,3,5-F3 I3 B) to form cocrystals of the organoiodines with the trimethylphenylammonium triiodide (NMe3 PhI3 ) salt. Single-crystal X-ray crystallography revealed the (I3 )- anion served as a halogen bond acceptor for the organoiodine donors, forming a variety of 1-D, 2-D, and 3-D packing arrangements through I⋅⋅⋅I halogen bonding. Significant asymmetry was observed within the (I3 )- anion. The melting points of the cocrystalline materials, as determined by simultaneous DSC/TGA, ranged from 43 °C to 119 °C and showed a strong dependence on the identity of the organoiodine incorporated into the crystal lattice.