Erik Rakovský

Formulating fluticasone propionate in novel PEG-containing nanostructured lipid carriers (PEG-NLC)

The aim of this study was to develop nanostructured lipid carriers (NLC) for topical delivery of fluticasone propionate (FP) with the aim to further improve the safety profile and decrease the adverse-side effects commonly reported in topical corticotherapy. NLC are colloidal drug-carriers consisting of a blend of a solid lipid and a small amount of liquid lipid since these carriers have proved to be effective in epidermal targeting in particular of glucocorticoids. NLC consisting of glyceryl palmito-stearate, and PEG-containing medium chain triglycerides mixture, stabilised by polysorbate 80 and soybean phosphatidylcholine were prepared. A mean particle size between 380 and 408 nm and entrapment efficacy of 95% were obtained for FP-loaded NLC. The crystallinity and polymorphic phase behaviour of FP-free and FP-loaded NLC were examined by differential scanning calorimetry and wide angle X-ray diffraction. Results revealed a low-crystalline structure and confirmed the incorporation of FP into the particles. The suitability of PEG-containing liquid lipids to form the lipid matrix of NLC was also confirmed.

In situ photoexcitation of silver-doped titania nanopowders for activity against bacteria and yeasts

Photocatalytic and in situ microbial activity of the amorphous and annealed states of Ag-doped and un-doped titania were examined. Studies on their structure, morphology, composition, and the photo-absorption characteristics of these materials were performed. These results were correlated with the photocatalytic and microbial activity against methicillin resistant Staphylococcus aureus K324 (MRSA), methicillin susceptible S. aureus ATCC 25923 (MSSA), Escherichia coli PA 170, and yeasts Candida albicans ATCC 90028. The annealed powders containing anatase form of titania exhibited relatively higher photocatalytic activity,corresponding to activity against MRSA,when exposed to UV-A radiation. In comparison, amorphous powders exhibited low photoactivity and showed poor antibacterial performance against MRSA under UV-A exposure. Doping of amorphous titania with Ag resulted in an anti-MRSA effect without exposure to UV radiation. In the Ag-doped crystalline anatase samples, the size of Ag primary nanocrystallites increased, which led to the decrease in the surface concentration of Ag and detriment anti-MRSA activity.

Hexakis[3-(aminocarbonyl)pyridinium] decavanadate(V) dihydrate.

The structure of the title compound, (C(6)H(7)N(2)O)(6)[V(10)O(28)].2H2O, at 120 (2) K has monoclinic (C2/c) symmetry. The asymmetric unit consists of one half-decavanadate anion of Ci symmetry, three cations and one water molecule. Each water molecule is hydrogen bonded to two decavanadate anions, thus forming a one-dimensional chain of anions. The three-dimensional supramolecular structure is formed by a network of N-H...O, O-H...O and C-H...O hydrogen bonds, in which the cations, anions and water molecules are involved, and by nonparallel-displaced pi-stacking interactions between pyridine rings. As a result of hydrogen bonding, the carboxamide groups of the cations are somewhat twisted from the pyridine ring plane.

Bis[2‐(2‐hydroxyethyl)pyridinium] μ‐decavanadato‐bis[pentaaquamanganate(II)] tetrahydrate

The structure of the title compound, (C(7)H(10)NO)(2)[Mn(2)V(10)O(28)(H(2)O)(10)].4H(2)O or (C(5)H(4)NHCH(2)CH(2)OH)(2)[{Mn(H(2)O)(5)}(2)V(10)O(28)].4H(2)O, at 293 (2) K has triclinic (P\overline{1}) symmetry. The asymmetric unit consists of one half of a decavanadate anion of C(i) symmetry, one [Mn(H(2)O)(5)](2+) group, one 2-(2-hydroxyethyl)pyridinium cation and two solvent water molecules. The decavanadate ion bridges between two [Mn(H(2)O)(5)](2+) groups, thus forming a dodecanuclear complex unit. Complex units are connected via a hydrogen-bonding network, forming supramolecular layers lying in the (001) plane. Cations and solvent water molecules are located between these layers.

Tetrakis(2,6-di­methyl­pyridinium) di­hydrogen deca­vanadate dihydrate

The structure of the title compound, (C7H10N)4[H2V10O28]·2H2O, was solved from a non-merohedrally twinned crystal (ratio of twin components ∼0.6:0.4). The asymmetric unit consists of one-half decavanadate anion (the other half completed by inversion symmetry), two 2,6-dimethylpyridinium cations and one water molecule of crystallization. In the crystal, the components are connected by strong N—H⋯O and O—H⋯O hydrogen bonds, forming a supramolecular chain along the b-axis direction. There are weak C—H⋯O interactions between the chains.

catena-Poly[[(pyrazine-2-carboxamide-κN4)copper(I)]-μ3-iodido]

In the title metal–organic polymeric complex, [CuI(C5H5N3O)]n, the asymmetric unit is composed of one monomer unit of the polymer and one CuI atom linked to one iodide anion and one pyrazine-2-carboxamide molecule. The CuI atom is in a distorted tetrahedral coordination completed by one pyrazine N atom of the pyrazine-2-carboxamide ligand and three iodide anions. The polymeric structure adopts a well-known ladder-like motif of {CuNI3} tetrahedra running in the b-axis direction. The molecules of the organic ligand are connected via medium-to-strong N—H⋯O and N—H⋯N hydrogen bonds and weak π–π interactions [the distance between two parallel planes of the rings is 3.5476 (14) Å and the centroid–centroid contact is 4.080 (2) Å]. The title compound has a relatively high decomposition temperature (564 K) as a result of relatively strong covalent and non-covalent interactions inside and between the chains.