Pharmaceutical technology offers various dosage forms that can be applied interdisciplinary. One of them are spherical pellets which could be utilized as a carrier in emerging second-generation detection tubes. This detection system requires carriers with high specific surface area (SSA), which should allow better adsorption of toxic substances and detection reagents. In this study, a magnesium aluminometasilicate with high SSA was utilized along with various concentrations of volatile substances (menthol, camphor and ammonium bicarbonate) to increase further the carrier SSA after their sublimation. The samples were evaluated in terms of physicochemical parameters, their morphology was assessed by scanning electron microscopy, and the Brunauer-Emmett-Teller (BET) method was utilized to measure SSA. The samples were then impregnated with a detection reagent o-phenylenediamine-pyronine and tested with diphosgene. Only samples prepared using menthol or camphor were found to show red fluorescence under the UV light in addition to the eye-visible red-violet color. This allowed the detection of diphosgene/phosgene at a concentration of only 0.1 mg/m3 in the air for samples M20.0 and C20.0 with their SSA higher than 115 m2/g, thus exceeding the sensitivity of the first-generation DT-12 detection tube.

• Klíčová slova
• BET method, chemical warfare agent, detection tube, extrusion, metasilicate, phosgene, porous pellets, spheronization, volatile substance,
• Publikační typ
• časopisecké články MeSH

The aim of the presented research was the preparation of an innovative carrier with significantly improved properties for the fast and sensitive detection of cholinesterase inhibitors such as nerve agents. This innovative carrier was in the form of spherical pellets containing different amounts of Neusilin. Neusilin is a synthetic and amorphous form of magnesium aluminometasilicate with a high specific surface area, and the immobilized enzyme butyrylcholinesterase with an activity of 50nkat·g-1. Pellets were prepared by the extrusion-spheronization method and dried in a hot air oven under two conditions - at 30°C for 72h and at 60°C for 24h. Dried pellets were consequently impregnated with a solution containing butyrylcholinesterase. Impregnated pellets were evaluated for their quality parameters, enzymatic activity and inhibition. Activity and inhibition were tested according to the standard Ellman's method. It was observed that the addition of Neusilin significantly increased the hardness, intraparticular porosity, sphericity and activity of the carriers as well as intensity of the color transition. Therefore it is shown that these carriers have unquestionable advantages over common carriers of their kind. Drying temperatures have been shown to have no effect on properties of pellets except for a change in their size. Results were confirmed by statistical evaluation using ANOVA and PCA.

• Klíčová slova
• Detection, Immobilization, Neusilin, Pellets, Physostigmine, Sarin,
• MeSH
• butyrylcholinesterasa chemie   MeSH
• celulosa chemie   MeSH
• cholinesterasové inhibitory chemie   MeSH
• enzymy imobilizované chemie   MeSH
• fysostigmin chemie   MeSH
• lékové formy MeSH
• nosiče léků chemie   MeSH
• pomocné látky chemie   MeSH
• poréznost MeSH
• povidon chemie   MeSH
• sarin MeSH
• silikáty chemie   MeSH
• sloučeniny hliníku chemie   MeSH
• sloučeniny hořčíku chemie   MeSH
• tvrdost MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aluminum magnesium silicate MeSH Prohlížeč
• butyrylcholinesterasa MeSH
• celulosa MeSH
• cholinesterasové inhibitory MeSH
• enzymy imobilizované MeSH
• fysostigmin MeSH
• lékové formy MeSH
• microcrystalline cellulose MeSH Prohlížeč
• nosiče léků MeSH
• pomocné látky MeSH
• povidon MeSH
• sarin MeSH
• silikáty MeSH
• sloučeniny hliníku MeSH
• sloučeniny hořčíku MeSH

The high specific surface area of multilayered two-dimensional carbides called MXenes, is a critical feature for their use in energy storage systems, especially supercapacitors. Therefore, the possibility of controlling this parameter is highly desired. This work presents the results of the influence of oxygen concentration during Ti₃AlC₂ ternary carbide-MAX phase preparation on α-Al₂O₃ particles content, and thus the porosity and specific surface area of the Ti₃C₂Tx MXenes. In this research, three different Ti₃AlC₂ samples were prepared, based on TiC-Ti₂AlC powder mixtures, which were conditioned and cold pressed in argon, air and oxygen filled glove-boxes. As-prepared pellets were sintered, ground, sieved and etched using hydrofluoric acid. The MAX phase and MXene samples were analyzed using scanning electron microscopy and X-ray diffraction. The influence of the oxygen concentration on the MXene structures was confirmed by Brunauer-Emmett-Teller surface area determination. It was found that oxygen concentration plays an important role in the formation of α-Al₂O₃ inclusions between MAX phase layers. The mortar grinding of the MAX phase powder and subsequent MXene fabrication process released the α-Al₂O₃ impurities, which led to the formation of the porous MXene structures. However, some non-porous α-Al₂O₃ particles remained inside the MXene structures. Those particles were found ingrown and irremovable, and thus decreased the MXene specific surface area.

• Klíčová slova
• MAX phases, MXenes, Ti3AlC2, Ti3C2Tx, porosity, α-Al2O3 particles,
• Publikační typ
• časopisecké články MeSH

Mycelium of the mold Aspergillus niger was used as a raw material for the preparation of microbial chitosan. Aspergillus niger, the mold used for the production of citric acid, contains approx. 15% of chitin, which can be separated, transformed into chitosan, and used as a sorbent for chromatography. The main advantage of this material in comparison with krill chitosan is the uniformity of particle size leading to the low back-pressure in the column. The other advantage is the fact, that original fibrous structure of mycelial pellets could be stabilized before chitosan preparation by cross-linking with glutaraldehyde. The product prepared by this way -- crosslinked chitosan of uniform particle size, is highly porous, with high water regain and, as a result, low sedimentation velocity. Low sedimentation velocity is not disadvantage in chromatographic application, but may form some problems in batchwise operation. Chitosan as a polymer of glucosamine is anion exchanger in nature and the chromatographic properties of this anion exchanger was demonstrated by the chromatography of bovine blood plasma, glucose oxidase, and chicken pepsinogen. In all cases, the course of chromatography on crosslinked chitosan was compared with the chromatography on MONO Q (bovine blood plasma) or DEAE-cellulose (glucose oxidase, chicken pepsinogen) under the same protocol.

• MeSH
• chitosan chemie   MeSH
• chromatografie iontoměničová přístrojové vybavení   MeSH
• houby chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chitosan MeSH