Permanent and systematical attention must be paid to the care how to protect health of workers in processes of freeze-drying and conservation of biological objects by means of low temperatures. Biohazards include also development of occupational diseases. Preventive care provided to workers is recommended in the form of admission and periodical checks. Some other own experience is presented in this paper, valid health service regulations are quoted together with recommendation how to prevent occupational injuries and secure observation of the above regulations by the employer organizations.

• MeSH
• kryoprezervace * MeSH
• lidé MeSH
• lyofilizace * MeSH
• nemoci z povolání etiologie   prevence a kontrola   MeSH
• primární prevence MeSH
• zdravotničtí pracovníci * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The effects of different drying temperatures (50, 60, 70 °C) on the quality of rose (Rose electron) petals were evaluated in this study. Drying time decreased from 1680 s to 600 s with increased infrared temperature. The temperature and time were increased from 50 °C to 70 °C and 30 min to 60 min, respectively, and a decrease in the fruit color quality was observed. The projected area (PA) of rose petals was affected significantly from temperature. After the drying process, the largest PA was observed as 33.35 cm2 (50 °C, 30 min), while the smallest achieved at 70 °C, 60 min (27.96 cm2). Depending on the temperature values (50, 60, 70 °C), the average projection area of dry samples of the rose petals decreased 2.17 times compared to the projection area of fresh samples. The dried samples demonstrated an increase in the total phenolic (TP) content compared to the fresh samples. The maximum TP (44.49 mg GAE/g) was achieved at 45 min and 70 °C rose petals sample. The results concluded that infrared drying for 45 min at 70 °C could be recommended for drying rose (rosa electron) petals.

• Klíčová slova
• drying process, infrared drying, rose petals, total phenolic content,
• Publikační typ
• časopisecké články MeSH

The paper discusses the real-time monitoring of the changing sample morphology during the entire lyophilization (freeze-drying) and vacuum-drying processes of model biopharmaceutical solutions by using an environmental scanning electron microscope (ESEM); the device's micromanipulators were used to study the interior of the samples in-situ without exposing the samples to atmospheric water vapor. The individual collapse temperatures (Tc) of the formulations, pure bovine serum albumin (BSA) and BSA/sucrose mixtures, ranged from -5 to -29 °C. We evaluated the impact of the freezing method (spontaneous freezing, controlled ice nucleation, and spray freezing) on the morphologies of the lyophiles at the constant drying temperature of -20 °C. The formulations with Tc above -20 °C resulted in the lyophiles' morphologies significantly dependent on the freezing method. We interpret the observations as an interplay of the freezing rates and directionalities, both of which markedly influence the morphologies of the frozen formulations, and, subsequently, the drying process and the mechanical stability of the freeze-dried cake. The formulation with Tc below -20 °C yielded a collapsed cake with features independent of the freezing method. The vacuum-drying produced a material with a smooth and pore-free surface, where deep cracks developed at the end of the process.

• Klíčová slova
• Bovine serum albumin, Environmental scanning electron microscopy, Freeze-drying, Vacuum-drying,
• MeSH
• farmaceutická chemie MeSH
• lyofilizace metody   MeSH
• mikroskopie elektronová rastrovací metody   MeSH
• nízká teplota MeSH
• sacharosa chemie   MeSH
• sérový albumin hovězí chemie   MeSH
• vakuum MeSH
• vysoušení metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• sacharosa MeSH
• sérový albumin hovězí MeSH

Spent coffee ground (SCG) is an environmental nuisance material, but, if appropriately processed it can be converted into pellets, and thus, used as an energy source. The moisture content of the final product should be below 10%, to ensure safe storage, and elimination of microorganism growth (particularly moulds). The present study aims to identify the optimal drying process for removing moisture from SCG and to investigate changes to the composition of SCG due to drying, at temperatures around 75 °C, so that the dried SCG to qualify as renewable energy source. Three drying processes were employed for SCG drying (with initial moisture content of about 65%): oven drying, solar drying and open air sun drying, while SCG samples were placed in aluminium trays with thicknesses of 1.25, 2.5 and 4 cm. Based on the experimental results for SCG samples with thickness 2.5 cm, the open air sun drying process required 10 h to reach final moisture content of 37%, while solar drying achieved 10% moisture content in 10 h and oven drying achieved 7% moisture content in 6 h. The solar drying process proved as the most advantageous, due to low energy requirements and adequate quality of dried SCG. Also, experiments indicated that SCG storage at "normal room conditions" resulted to equilibrium moisture content in SCG of 8%, regardless of the initial moisture content. Furthermore, instrumental analyses of the SCG, revealed changes to its composition for a number of chemical groups, such as aldehydes, ketones, phytosterols, alkaloids, lactones, alcohols, phenols, pyrans and furans, among others. It was also identified that the SCG colour was affected due to the drying process.

• Klíčová slova
• Colour, Drying, Hemicellulose, Lignin, Mould, Spent coffee ground,
• MeSH
• fenoly MeSH
• káva * MeSH
• obnovitelná energie MeSH
• teplota MeSH
• vysoušení * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fenoly MeSH
• káva * MeSH

Methods commonly used for soil sample preparation may be unsuitable for measuring Hg concentrations due to the possible loss of volatile Hg species when drying at higher temperatures. Here, the effects of freeze-drying, air drying at 25°C and oven-drying at 105°C on Hg concentrations in two soil types and three standard reference materials were tested. Two soils with different levels of Hg contamination and three reference materials were examined. A systematic decrease of Hg concentrations was observed in air-dried (24 %) and oven-dried (3 %) contaminated upland soils in comparison to freeze-dried control samples. The 105°C oven drying also led to loss of Hg from reference materials (5 %-8 % in comparison with the certified Hg concentration). Different results from the drying of sterilized reference materials and natural soils were probably related to the extent of microbiological activity, demonstrating the importance of this parameter in sample preparation for Hg analysis.

• MeSH
• látky znečišťující půdu analýza   MeSH
• lyofilizace MeSH
• monitorování životního prostředí metody   MeSH
• půda chemie   MeSH
• rtuť analýza   MeSH
• vysoká teplota MeSH
• vysoušení MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• látky znečišťující půdu MeSH
• půda MeSH
• rtuť MeSH

Microtubules represent cytoplasmic structures that are indispensable for the maintenance of cell morphology and motility generation. Due to their regular structural organization, microtubules have become of great interest for preparation of in vitro nanotransport systems. However, tubulin, the major building protein of microtubules, is a thermolabile protein and is usually stored at -80 degrees C to preserve its conformation and polymerization properties. Here we describe a novel method for freeze-drying of assembly-competent tubulin in the presence of a nonreducing sugar trehalose. Even after prolonged storage at ambient temperature, rehydrated tubulin is capable of binding antimitotic drugs and assembling to microtubules that bind microtubule-associated proteins in the usual way. Electron microscopy confirmed that rehydrated tubulin assembles into normal microtubules that are able to generate motility by interaction with the motor protein kinesin in a cell-free environment. Freeze-drying also preserved preformed microtubules. Rehydrated tubulin and microtubules can be used for preparation of diverse in vitro and in vivo assays as well as for preparation of bionanodevices.

• MeSH
• kineziny metabolismus   MeSH
• kolchicin chemie   metabolismus   MeSH
• lyofilizace metody   MeSH
• mikrotubuly chemie   metabolismus   MeSH
• stabilita proteinů MeSH
• teplota MeSH
• trehalosa chemie   MeSH
• tubulin chemie   metabolismus   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kineziny MeSH
• kolchicin MeSH
• trehalosa MeSH
• tubulin MeSH

Spray drying and hot-melt extrusion are among the most prevalent preparation techniques used in the pharmaceutical industry to produce amorphous solid dispersions (ASDs). This study advances previous research by integrating sample production, comprehensive analytical characterization, intrinsic dissolution rate measurements, and assessments of the behavior of ASDs under elevated temperature and humidity conditions. The study focuses on indomethacin, a widely used model for poorly soluble drugs, processed with PVP K30 or HPMC E5, both commonly used polymers. The findings demonstrate that hot-melt extruded samples exhibit superior stability against recrystallization, whereas spray dried samples achieve higher intrinsic dissolution rates. Furthermore, PVP K30 significantly outperforms HPMC E5 in the co-processing of indomethacin, enhancing both the intrinsic dissolution rate and the stability.

• Klíčová slova
• Amorphous solid dispersions, Dissolution, Hot-melt extrusion, Recrystallization, Spray drying, Stability,
• MeSH
• deriváty hypromelózy chemie   MeSH
• farmaceutická chemie metody   MeSH
• indomethacin * chemie   MeSH
• krystalizace * MeSH
• povidon chemie   MeSH
• příprava léků metody   MeSH
• rozpustnost * MeSH
• sprejové sušení * MeSH
• stabilita léku * MeSH
• technologie extruze tavenin * metody   MeSH
• uvolňování léčiv MeSH
• vlhkost MeSH
• vysoká teplota MeSH
• vysoušení metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• deriváty hypromelózy MeSH
• indomethacin * MeSH
• povidon MeSH

Fast-drying and cooling induce fast intracellular water loss and reduced ice-crystal formation, which may promote the formation of intracellular glasses that might improve the likelihood of wheat pollen survival. Long-term storage of pollen is important for the fertilization of spatially or temporally isolated female parents, especially in hybrid breeding. Wheat pollen is dehydration-sensitive and rapidly loses viability after shedding. To preserve wheat pollen, we hypothesized that fast-drying and cooling rates would increase the rate of intracellular water content (WC) removal, decrease intracellular ice-crystal formation, and increase viability after exposure to ultra-low temperatures. Therefore, we compared slow air-drying with fast-drying (dry air flow) and found significant correlations between pollen WC and viability (r = 0.92, P < 0.001); significant differences in WCs after specific drying times; and comparable viabilities after drying to specific WCs. Fast-drying to WCs at which ice melting events were not detected (ΔH = 0 J mg-1 DW, < 0.28 mg H2O mg-1 DW) reduced pollen viability to 1.2 ± 1.0%, but when drying to 0.39 mg H2O mg-1 DW, some viable pollen was detected (39.4 ± 17.9%). Fast cooling (150 °C min-1) of fast-dried pollen to 0.91 ± 0.11 mg H2O mg-1 DW induced less and a delay of ice-crystal formation during cryomicroscopic-video-recordings compared to slow cooling (1 °C min-1), but viability was low (4.5-6.1%) and comparable between cooling rates. Our data support that the combination of fast-drying and cooling rates may enable the survival of wheat pollen likely due to (1) a reduction of the time pollen would be exposed to drying-related deleterious biochemical changes and (2) an inhibition of intracellular ice-crystal formation, but additional research is needed to obtain higher pollen survival after cooling.

• Klíčová slova
• Cryomicroscopy, Differential scanning calorimetry, Hybrid breeding, Impedance flow cytometry, Pollen viability,
• MeSH
• diferenciální skenovací kalorimetrie MeSH
• elektronová kryomikroskopie MeSH
• kryoprezervace MeSH
• krystalizace MeSH
• led MeSH
• lyofilizace MeSH
• nízká teplota MeSH
• pšenice * MeSH
• pyl chemie   cytologie   fyziologie   MeSH
• vysoušení MeSH
• zmrazování MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• led MeSH

Spray drying is commonly used for producing amorphous solid dispersions to improve drug solubility. The development of such formulations typically relies on comprehensive excipient and composition screening, which requires the preparation of many spray-dried powder samples. This is both labour-intensive and time-consuming when carried out manually. In the present work, the formulation screening task was automated by coupling a laboratory spray dryer operated in a semi-continuous mode with custom-made add-ons, allowing for rapid, computer-controlled production of formulation samples with systematically varying composition. The practical use of the spray drying robot in formulation development was demonstrated on a case study of poorly water-soluble model drugs simvastatin and ezetimibe. Six different polymers and several drug:polymer ratios were screened for the enhancement of dissolution properties. From a pool of 28 spray-dried samples, ternary compositions containing Eudragit L100-55 were identified as the most suitable ones for further processing and characterisation. The ability to populate the formulation design space rapidly and automatically made it possible to construct maps of physico-chemical properties such as glass transition temperature or dissolution rate. The spray drying robot thus enables the acceleration of early formulation development and a deeper understanding of composition-property relationships for multi-component spray dried powders.

• Klíčová slova
• Amorphous solid dispersion, Dissolution rate enhancement, Eudragit, Ezetimibe, Glass transition temperature, Simvastatin,
• MeSH
• polymery chemie   MeSH
• příprava léků MeSH
• robotika * MeSH
• rozpustnost MeSH
• sprejové sušení * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• polymery MeSH

Buckwheat cookies with various ingredients for raw food vegan diet are usually prepared by soaking them in water at ambient temperature followed by drying at moderate temperature. The aim of this study was to examine the temperature effect on the microbiological quality, antioxidant properties and oxidative stability of lipids of final dried samples. The mixture of ingredients was soaked for 20 h in distilled water, and then cookies were formed and dried in air-forced oven at constant temperature in the range from 40 to 60 °C. Total viable counts, fungi, yeasts, coliform and aerobic spore-forming bacteria counts were evaluated in dried samples and were found to decrease during drying at 50 and 60 °C. Antioxidant activity was determined by DPPH and ABTS assays, and the former showed the highest value at 40 °C. Superoxide dismutase activity was also higher at 40 °C in comparison with that at 60 °C. The percentage of lipid peroxidation inhibition increased with the increase in drying temperature until 4th day of incubation. While peroxide value was significantly higher in samples dried at 40 °C, TBARS values did not show significant changes during the drying process. The results of this study suggest that drying buckwheat-based cookies at 40 °C retained their good antioxidant properties but represent a potentially serious microbial hazard.

• Klíčová slova
• Antioxidant, Drying process, Lipid peroxidation, Microbial risk, Raw food,
• MeSH
• antioxidancia analýza   farmakologie   MeSH
• bakteriální nálož MeSH
• dieta veganská * MeSH
• Fagopyrum chemie   mikrobiologie   MeSH
• kontaminace potravin analýza   MeSH
• látky reagující s kyselinou thiobarbiturovou analýza   MeSH
• manipulace s potravinami MeSH
• peroxidace lipidů MeSH
• potravinářská mikrobiologie MeSH
• superoxiddismutasa metabolismus   MeSH
• syrová strava analýza   MeSH
• teplota MeSH
• voda analýza   MeSH
• vysoušení * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• látky reagující s kyselinou thiobarbiturovou MeSH
• superoxiddismutasa MeSH
• voda MeSH