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U periodu od 19. do 21. svibnja 2023. na Zagrebačkom Velesajmu, u Paviljonu 10A, održan je II. MUZZA TJEDAN ZNANOSTI. Sveučilište u Zagrebu Fakultet kemijskog inženjerstva i tehnologije kao parter ovog događaja se prezentirao s temom MI VIDIMO NEVIDLJIVO! Osmišljen je prostor (MUZZA LAB) i organizirano je 17 radionica koje je tijekom tri dana održavalo 80 nastavnika, suradnika i studenata FKIT-a. MUZZA LAB je prostor od 90 m2 koji je bio podijeljen u četiri zone (plava, zelena, crvena i narančasta). Na svakoj od četiri zone izmjenjivale su se interaktivne radionice koje su činile tematsku cjelinu i uklapale se u poruku "Mi vidimo nevidljivo". Radionice su se održavale u puni sat (10-19 sati) i trajale 30 min. Tijekom tri dana ukupno je održano 108 radionica u kojima je sudjelovalo preko 1200 sudionika u dobi od 5 do 12 pa i više godina. MUZZA LAB je održan u sklopu promicanja znanosti i Fakulteta kemijskog inženjerstva i tehnologije u STEM području. Temom "Mi vidimo nevidljivo" se željela poslati poruka da je sve oko nas složeno, slojevito, skriveno, ali ne i nedokučivo. Promotrimo svijet drugim „očima“ i otkrit ćemo njegovu ljepotu.

The commencement of ceria use for advanced catalytic applications took place a few decades ago and regardless of being widely used in catalysis, it is still being researched to improve its properties and catalytic efficiency. Besides in catalysis, owing to its fluorite structure and easy shift between Ce3+ and Ce4+ oxidation state, ceria utilization is investigated in solid oxide fuel cells and water purification membranes. Manganese, having multiple oxidation states, is assumed to improve many of CeO2 properties including catalytic activity. As a catalyst, ceria is mostly utilized as a part of exhaust gas oxidation catalyst in three-way automobile catalytic converters and soot oxidation catalysts in diesel particulate filters, as well as for the oxidation of volatile organic compounds. In this investigation ceria (CeO2) nanoparticles doped with manganese in various amounts were prepared via hydrothermal synthesis. The prepared samples were thermally treated at 500 °C for 2 hours to prevent change of properties in the course of catalytic test at elevated temperatures. Thermally treated samples were investigated via X-ray diffraction (XRD) and energy dispersive X-ray spectrometry (EDS) to determine the phase and elemental composition, while N2 adsorption- desorption isotherms were used for the determination of specific surface area. Finally, catalytic activity of the prepared catalyst was tested on benzene, toluene, ethylbenzene and o- xylene (BTEX) gas mix. It was established that doping of manganese into the ceria structure has noticeable benefits for the catalyst activity in BTEX oxidation process.

Od 19. do 21. svibnja 2023.na Zagrebačkom Velesajmu, u Paviljonu 10A, održano je drugo izdanje MUZZA Tjedna Znanosti. U sklopu MUZZA LAB- a održano je je devet radionica "Osjeti molekule u virtualnoj stvarnosti" koje su bile dobro posjećene. Radionice su održane u sklopu promicanja znanosti i Sveučilišta u Zagrebu Fakulteta kemijskog inženjerstva i tehnologije u STEM području pod nazivom "Mi vidimo nevidljivo".

Nasal delivery of the anti-dementia drug donepezil hydrochloride (DH) presents an alternative route of administration directly to the brain. Nasal powders stand out as formulations with great potential for nose-to-brain delivery. However, due to close contact of powders and the mucosa, formulations can cause stinging, itching and/or burning (SIB) sensations. The slug mucosal irritation assay is a quick and accurate screening method for early prediction of nasal discomfort caused by powders. DH-loaded chitosan, chitosan/mannitol and chitosan/lactose microspheres were prepared by spray-drying (Büchi Mini Spray Dryer B-290, equipped with ultrasonic nozzle). Furthermore, DH-loaded chitosan microspheres were blended (Turbula® shaker mixer) with sieved (45-63 µm) or spray-dried mannitol and lactose, reaching the same constituent weight ratios as in spray-dried hybrid microspheres. The particle size distribution and morphology were determined by laser diffraction method (Malvern Mastersizer 3000) and scanning electron microscopy (Tescan Vega 3), respectively. The slug mucosal irritation assay was performed to screen the powders regarding their potential to cause SIB sensations. DH-loaded nasal powders were successfully prepared by spray-drying and/or powder blending. All spray-dried particles (Dv50 9.7±0.0-29.0±1.2 µm) were smaller than sieved lactose and mannitol. The tested nasal powders showed either no discomfort or mild discomfort. Statistically significant increase in irritability compared to negative control was observed only for DH-loaded chitosan microspheres and their mixture with sieved lactose. The obtained results indicate the superior sensory effects of hybrid microspheres compared to chitosan microspheres and reveal the possible combined impact of filler particle size and morphology on the powder blend irritability. Slug mucosal irritation assay proved to be a useful tool for evaluation of nasal discomfort early in the formulation development. Prepared DH powders generally showed low irritability, confirming the appropriate selection of excipients and suitability of the spray-drying process to adjust particle morphology.

Grinding is one of the most widely used methods of obtaining solid particles of controled/ desired distribution systems in all branches of industry. Enlargement of this process is often based on experience and on trial and error methods that requires a large number of experiments. The development of mathematical models enabled the transfer of results to a larger scale in similar systems. The proposed researches were conducted in a laboratory scale. The modeling of the grinding process by the population balance included a description of the kinetics of dolomite grinding by kinetic parameters and the development of models that enabled the estimation of kinetic parameters on the basis of the particle size, the geometric characteristics of the mill and the process parameters. Rajamani and Herbst model is suggested for the development of selection function in a ball mill under given conditions process. The selection function was determined based on the change in the proportion of unbroken material over time for eight size intervals in four mills of different volumes, using one-size interval method. Change of unbroken material content with time is linear.The specified dependence suggests first-order breakage kinetics. The selection function was then described by the Rajamani Herbst model. Laboratory-level researches and the development of mathematical models for transferring results to a larger scale is a potential way of reducing energy consumption.

Ovo je službeni dokument, samoanaliza Fakulteta kemijskog inženjerstva i tehnologije Sveučilišta u Zagrebu za reakreditaciju u 2022.

A recent investigation of doped ceria catalyst, as well as advanced synthesis methods of ceria catalyst support will be presented. First, the optimization of the hydrothermal synthesis process in order to obtain as small crystallites as possible, as well as testing of the catalytic activity of the prepared nanocatalysts will be described. Then, the properties of ceria doped with various transition metal ions will be presented, after which the focus will be on ceria doped with manganese and copper, which have proven to be the most effective catalysts. Particularly, crystal phases and distribution of manganese, grain growth kinetics, properties and catalytic activity of manganese doped hydrothermally derived ceria, as well as doping levels, thermal stability, properties and catalytic activity of copper doped hydrothermally derived ceria will be presented. Other synthesis procedures such as sol- gel and mechanochemical synthesis will be also presented, as well as the use of doped ceria for other purposes such as UV filter, with focus on cell toxicity, and humidity sensing thin films. Finally, several possible directions of research in the field of synthesis, utilization and properties of ceria and doped ceria nanomaterials will be proposed.

The most prominent and recently explored use of ceria nanoparticles is the catalytic ability of metal-doped ceria and its suitability for oxidation of various pollutants. Different metal ions can penetrate the ceria lattice. However, the choice of metals and their ability to enter the lattice depends on the choice of synthesis route. Doped ceria exhibits higher catalytic activity because it has a greater oxygen storage capacity and a larger specific surface area. Numerous techniques for the synthesis of ceria and ceria- doped nanoparticles have been reported in the literature, such as mechanochemical synthesis, sol-gel, hydrothermal synthesis, precipitation, thermal decomposition, etc. In this work, pure ceria and manganese-doped ceria previously prepared by sol-gel [1], hydrothermal [2] and mechanochemical [3] synthesis were analyzed. Analysis of variance (ANOVA) was used to evaluate the influence of manganese content and synthesis method on the specific surface area and conversion ability of the prepared samples. Manganese-doped ceria nanoparticles were prepared by sol-gel, hydrothermal, and mechanochemical methods followed by thermal treatment at 500 °C for 2 hours. Four samples were obtained by each method, pure ceria and samples doped with 10%, 20% and 30% manganese. Specific surface areas were determined by N2 gas adsorption-desorption isotherms from Micromeritics ASAP2000 instrument at –196 °C. The samples were previously degassed at 100 °C under a dynamic vacuum of 7 mPa. The activities of the prepared catalysts were measured in an integral up-flow fixed bed reactor at atmospheric pressure [4]. Toluene was used as a model volatile organic compound. The catalytic oxidation of toluene was carried out under isothermal conditions and in a temperature range from 100 to 500 ºC. The toluene conversions obtained at 200 °C were used for statistical analysis. StatEase Design Expert 7.0 software was used for statistical analysis of the data obtained. Specific surface area (SSA) and toluene conversion (TC) were analyzed based on the variation of two factors, manganese content (numerical factor) and synthesis method (categorical factor). Based on the R-squared values, the analysis showed that the linear model should be used to predict the specific surface area. On the other hand, the 2FI (two-factor interaction) model was proposed for the evaluation of toluene conversion. Analysis of variance revealed statistically significant models confirmed by low p-values: 0.0103 for SSA and 0.0003 for TC (square root transformation), and high F-values: 7.5 for SSA and 31.31 for the square root of TC. The residuals in the normal plot were linear, supporting the condition that the error terms are normally distributed. Numerical optimization showed desirable results using the criteria of maximized specific surface area as well as maximized toluene conversion (Fig. 1). The most desirable Mn content is 30% for all synthesis routes. However, the optimization showed that sol-gel synthesis is the preferred method since the result obtained for toluene conversion is 94.6% desirable. Statistical analysis led to models that can easily predict the specific surface area and toluene conversion results as a function of the amount of manganese dopant and the synthesis method chosen.

Nasal powders are promising platforms in nose-to- brain drug delivery (1). Spray drying is a single- step, fast and scalable dry powder preparation method (2). Design of experiments (DoE) is often used in product-related optimization of the spray drying process (2). The potential of ultrasonic nozzle for the preparation of nasal powders has not yet been deeply investigated. The aim of this study is to prepare donepezil loaded chitosan/mannitol microspheres by spray drying using an ultrasonic nozzle. Employing Quality by Design approach will enable elucidating and understanding the impact of formulation and process parameters on spray drying yield and microspheres physicochemical properties. Statistical DoE (JMP 14.0 software, USA) was employed in optimisation of spray dried donepezil hydrochloride (DH ; Carbosynth Ltd, UK) loaded chitosan (Sigma Aldrich, USA) and mannitol (BDH Prolabo, UK) microspheres. The following properties were observed as responses: process yield, entrapment efficiency (high performance liquid chromatography ; Perkin Elmer, USA), particle size (Mastersizer 3000 ; Malvern Instruments Ltd, UK) and moisture content (TA Instruments Q500 ; TA Instruments, USA). Microspheres morphology and surface properties were observed by scanning electron microscopy (SEM) using a Tescan Vega 3 microscope (Czech Republic). Spray dried chitosan/mannitol microspheres with high DH entrapment efficiency and adequate moisture content were successfully prepared using an ultrasonic nozzle, fitting the size requirements for targeted nasal delivery (majority of particles larger than 10 µm). Process yield was in line with literature reports. Regression modelling revealed the impact of both, formulation and process parameters on yield, moisture content and particle size. The obtained microspheres were uniform and spherical with smooth surface, as showed by SEM micrographs. This study confirmed the suitability of ultrasonic nozzle for preparation of microspheres for nasal drug delivery. Predictive power of regression model obtained for observed responses enables the development of donepezil loaded chitosan/mannitol nasal powder platform with built-in quality, maximizing cost and time savings. References: 1. Giuliani A, Balducci AG, Zironi E, Colombo G, Bortolotti F, Lorenzini L, Galligioni V, Pagliuca G, Scagliarini A, Calzà L, Sonvico F. Drug Deliv. 2018. 25:376-387 2. Ziaee A, Albadarin AB, Padrela L, Femmer T, O’Reilly E, Walker G. Spray drying of pharmaceuticals and biopharmaceuticals: Critical parameters and experimental process optimization approaches. Eur J Pharm Sci. 2019 ; 12: 300–318.

Eriochrome black T (EBT) is an azo dye that is extensively used in the textile industry for dyeing of silk, nylon and wool. The decomposition of EBT produces carcinogenic products, while its presence in wastewater dramatically affects the aquatic ecosystem. Azo dyes are resistant to biological treatment, oxidizing agents, heat and light, which makes their removal from wastewater very problematic. Therefore, advanced oxidation processes such as photocatalytic decomposition are often utilized. In this paper, the process of photocatalytic degradation of EBT dye under UV radiation was monitored with nanoparticle copper doped cerium (IV) oxide (CuxCe1-xO2, x = 0, 0.1, 0.2 and 0.3) serving as the photocatalyst. CuxCe1-xO2 samples were prepared by hydrothermal method and analyzed by X-ray diffraction analysis, transmission electron microscopy, energy dispersive X-ray spectroscopy and N2 adsorption- desorption isotherms. Nanoparticles of sizes between 6 and 3.8 nm and specific surfaces of about 200 m2 g-1 were obtained. Photocatalytic tests showed that pure EBT does not degrade without the addition of photocatalysts, while all of the tested photocatalysts follow the adsorption kinetics of pseudo-second order and the photodegradation kinetics of pseudo-first order. The maximum reduction of EBT concentration is achieved with the sample Cu0.1Ce0.9O2.

Ceria (CeO2) is a material with many uses related to environmental protection and industry. Many of its applications depend on fluorite structure and easy shift between Ce3+ and Ce4+ oxidation states. During this interchange oxygen vacancies occur but thanks to its stable nature, the shift does not affect the cubic lattice. Some of the applications involving ceria are in catalysis, in solid oxide fuel cells and as a polishing material. Reducing dimensions to nanoscale is a good way to ensure greater specific surface area and catalytic activity. This makes the shift between Ce4+ and Ce3+ easier improving oxygen storage and mobility within the lattice. Another way of advancing ceria is doping. Ceria is mostly doped with transition metals. Most transition metals can enter the lattice thus enhancing catalytic activity and improving other properties while some don’t even enter the lattice. Manganese has many oxidation states and as such can improve oxygen storage and mobility and even thermal stability. There are many methods of synthesis for nanoparticles while advanced methods include hydrothermal, sol-gel and mechanochemical synthesis. Each of these methods has its advantages as well as problems such as harmful organic solvents, lack of temperature control or very small sample gain. In this work, our aim was to compare above mentioned methods of synthesis to prepare ceria as well as manganese doped ceria. The prepared samples were characterized by X-ray diffraction (XRD), infrared spectroscopy with Fourier transformation (FTIR) and N2 adsorption-desorption isotherms. Catalytic activity was tested on thermally treated samples at 500 °C for 2 hours. X-ray diffraction patterns were used to calculate ceria crystallite size via Scherrer equation. Each method of synthesis results with nanocrystalline ceria particles but in two of the used methods a minor phase appears beside CeO2. Smallest crystallite size was gained by the sol-gel synthesis. All samples show improved thermal stability with manganese incorporation.

Pure and manganese doped ceria samples were prepared via hydrothermal synthesis. After thermal treatment at 500°C for 2 hours, samples were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2 adsorption-desorption isotherms. XRD shows only the presence of fine ceria particles (ICDD 34- 0394). Crystallite size calculated by the Scherrer equation shows that manganese doping stabilizes nano ceria in the course of thermal treatment. Surface properties also benefit from manganese doping gaining greater specific surface area (SSA) and pore size values. While the volumes of the samples used in each of this analysis differ and methods are based on various models, nanoparticle sizes show reasonable concordance with all three methods used.

Ceria, CeO2, is an important rare earth oxide material with cubic fluorite type structure. Pure ceria is an n-type semiconductor with two stabile oxidation states, Ce3+ and Ce4+, making it suitable for various applications. [1] Energy and catalyst applications are mostly based on great oxygen storage capacity, redox properties and ionic conductivity of ceria. Ceria is frequently used in solid oxide fuel cells, catalysis, sensors and high temperature ceramics. [2] Good catalytic properties and ionic conductivity depend on thermal stability which nanomaterials lack. Doping with various metals, including transition metals such as manganese helps to overcome pure ceria shortcomings. Manganese is known to have many oxidation states and because of the synergistic effect between MnOx and CeO2 can modify oxygen storage capacity and mobility. Mechanochemical synthesis is a method that can yield fine homogenous powders. Intensive mechanical milling causes chemical reactions between precursors and results with products that usually form at much higher than room temperatures. Negative features of ball milling can be agglomeration or heat generated while milling. Nanoparticles of pure and Mn doped ceria were attained by mechanochemical synthesis from chlorides. After synthesis, x-ray diffraction (XRD) and differential thermal analysis (DTA) were performed giving insight into acquired phases and their thermal decomposition. Scherrer equation was used on 500°C for 2h annealed samples to calculate ceria crystallite size. Morphology of the prepared samples was investigated on a scanning electron microscope (SEM), while N2 adsorption-desorption isotherms gave insight into surface and pore features. Catalytic character of doped and pure ceria samples was measured via toluene conversion in a 150°C – 450°C temperature interval. All of the prepared samples show pure ceria phase after thermal treatment. DTA and XRD results show that the incorporation of manganese in ceria enables easier ceria formation as well as generates smaller crystallites.

In the last 20 years, organic micropollutants (OMPs) have gained significant attention because of their possible impact on the environment. Besides, they cannot be easily removed by conventional wastewater treatment technologies. TiO2 heterogeneous photocatalysis is actively studied as an alternative technology for the degradation and/or removal of OMPs. Therefore, this study focuses on the synthesis of enhanced photocatalyst, which could use visible light for activation, using the non-conventional microwave-assisted method, and evaluating the role of the temperature and reaction time on the morphological properties of the synthesized materials. Nitrogen-doped TiO2 (N/TiO2) photocatalyst was synthesized by the microwave-assisted method using varying temperatures and reaction times. The obtained materials were characterized by XRD, FTIR and N2 adsorption isotherms. The only crystalline phase present in the N/TiO2 materials was anatase. Higher crystallinity and greater crystallite size were achieved for synthesis at higher temperature. N/TiO2 materials’ photocatalytic activity was evaluated for the degradation of ciprofloxacin under UV and visible light. They show photoactivity under both UV and visible light, while commercial photocatalyst Degussa P25 TiO2 shows activity only under UV light. Better photoactivity was achieved with materials synthesized at a higher temperature, whereas reaction time in the microwave oven has a negligible effect on the morphologic and photocatalytic properties. Temperature was found to be the crucial parameter in the synthesis of N/TiO2 by the microwave-assisted method.

Koliko puta ste pokušali promiješati prašak, ali bezuspješno? One svojevoljne velike čestice uvijek izviruju na vrhu mješavine. Taj efekt naziva se segregacija, a događa se pri potresanju slobodno tecivih prašaka u kojima postoji razlika u veličinama čestica.

Cerijev(IV) oksid, CeO2 koristi se kao katalizator s različitim primjenama u području istraživanja stanja okoliša. Njegova dobra katalitička svojstva pripisuju se mogućnostima stvaranja vakancija kisika, visokoj mobilnosti kisika i kapacitetu skladištenja kisika unutar rešetke. Različiti manganovi oksidi imaju visoku katalitičku aktivnost te se vjeruje da će ugradnja Mn atoma u kristalnu rešetku CeO2 poboljšati njegova katalitička svojstva. Nanokristali čistog CeO2 te dopiranog manganom u različitim udjelima, pripremljeni su hidrotermalnom sintezom. Prednosti ovakvog pristupa su sinteza u jednoj reakcijskoj posudi, ekonomičnost te okolišna prihvatljivost, obzirom da je omogućena sinteza nanočestica pri niskim temperaturama u samo jednom koraku. Uzorci su termički obrađeni na više temperatura kako bi se pratila termička stabilnost i aglomeracija uzoraka. Također je na uzorcima praćena izotermna kinetika okrupnjavanja nanočestica. Veličina čestica određena je Scherrer-ovom metodom iz difraktograma rendgenske difrakcije uzoraka, dok je specifična površina pripremljenih nanočestica određena preko adsorpcijsko-desorpcijskih izoterma dušika. Primjenom Arrhenius-ove jednadžbe određene su energije aktivacije rasta kristala za sve uzorke. Primjećeno je povećanje energije aktivacije dopiranih uzoraka u odnosu na čisti CeO2. Morfologija pripremljenih uzoraka praćena je transmisijskim elektronskim mikroskopom (TEM).

3D printing technology is nowadays widely applied in pharmaceutical industry. A great number of formulations, including those containing multiple drugs, different geometry and release characteristics, have already been made leading to the concept of personalized medicine. The aim of this research was to produce tablets that contain dronedarone hydrochloride (DNR), with different tablet infill using fused deposition modeling and drug-loaded self-produced filaments. Two different blends containing dronedarone hydrochloride, polyvinyl alcohol and excipients such as polyethylene glycol or sorbitol, were made. Filaments were produced by hot melt extrusion at 170 °C, their diameter was measured and the content of DNR was determined. Fused deposition modeling was used for 3D printing of tablets with different material infill from the obtained filaments. Release profiles of DNR from manufactured tablets were obtained using in vitro tests. The results indicate that the filament made out of the blend that contains polyethylene glycol have smooth surface, slighter deviation from the target filament diameter (1, 75 mm) and from the expected DNR content (10 wt.%) than the filament containing sorbitol. The tablets made from polyethylene glycol containing filament have a compact structure that contributes to uniform release of DNR during 28 hours. Research shows that material infill have influence on release kinetic of DNR and that different tablet infills can be used to provide different doses from single filament. Release profiles were described using Hixson- Crowell model. The equation is often used to describe release from systems where the dissolution occurs in planes that are parallel to the drug surface and where the tablet dimensions diminish proportionally keeping initial geometrical form constant. Adjusted values of the coefficient of determination showed applicability of the model for tablets with 100% and 75% infill.

Cerium oxide (CeO2) is a technologically important semiconducting material which exhibits high mixed ionic and electronic conductivity, as well as high oxygen storage capacity due to the reversible redox reaction between Ce4+ and Ce3+ions within the ceria crystal lattice. One of the most notable applications of ceria is as a catalyst in three-way catalytic converters in automobile exhaust systems. Ceria interaction with alumina can help in the stabilization of the surface area of the γ-Al2O3 support through the formation of cerium aluminate (CeAlO3). Ceria is also used in solid oxide fuel cells (SOFCs), but its drawback is a lack of mechanical stability which can be improved by adding alumina. Literature shows that mixing ceria with other catalytically active substances like MnOx, CuO or noble metals like Pd can significantly enhance its catalytic performance in many chemical processes. Therefore, the goal of this research was to produce and characterize MOx-CeO2-Al2O3 mixed oxides. The method of choice was combustion synthesis with glycine as fuel, since we have gained favorable results in producing γ-alumina in this manner in our previous work. As-prepared samples of pure Al2O3, CeO2 and MnOx, as well as corresponding mixed oxides were synthesized and characterized by X-ray diffraction analysis (XRD), differential thermal and thermogravimetric analysis (DTA-TGA), Fourier transformed infrared spectroscopy (FTIR) and nitrogen adsorption/desorption isotherms. For mixed oxides, CeAlO3 phase was achieved. However, not all as-prepared samples were crystalline and all of them showed presence of residual nitrates on FTIR spectra, which is why thermal treatment at 800 °C for 2 hours was applied. Thermal treatment yielded with mixed oxides having crystallite sizes in the nano range and their catalytic activity was tested on the soot oxidation process.

Ceria (CeO2), with its stable fluorite structure and two interchangeable oxidation states, Ce4+ and Ce3+ has many excellent properties enabling its widespread use. Owing to the shift between Ce4+ and Ce3+, oxygen vacancies occur within the lattice resulting with high oxygen mobility and oxygen storage capacity of ceria. Nanoparticles have a larger specific surface area compared to bulk material and thus provide faster oxygen exchange, resulting in better catalytic activity. It is belived that incorporation of Mn atoms in ceria crystal lattice will ensure even better catalytic propeties for oxidation of numerous compounds, for instance: carbon monoxide, phenol, and volatile organic compounds. With all this in mind, nano-ceria doped with manganese in various amounts was prepared via sol-gel synthesis. The as prepared samples were thermally treated to observe coarsening and thermal stability. All samples, as prepared and annealed, were studied by X-ray diffraction (XRD). Along with ceria, manganese (II) 2, 4-pentadionate [Mn(C5H7O2)2] lines appear in all of the as prepared samples doped with manganese. Crystallite size decrease due to incorporation of Mn atoms in the ceria crystal lattice was established via Scherrer method. The determination of surface properties as well as pore volume was acquired using Brunauer-Emmet-Teller (BET) N2 gas adsorption- desorption isotherms. Scanning electron microscope (SEM) analysis gave insight into sample morphology showing ceria nanoparticles. Thermally induced changes were monitored via differential thermal analysis and thermo- gravimetric analysis (DTA/TGA) giving insight into the decomposition of leftover organic phase.

Most approaches to porous materials syntheses require the use of templates for gaining the requested morphology and thus are complex, time consuming and costly. Due to its effectiveness and low cost, combustion synthesis is used as an alternative method of porous materials synthesis. It does not need to use a template because of the formation of gases which create a porous structure while escaping the sample. It can be used for production of nanoparticles and gives a pure, homogeneous oxide powder. Alumina was prepared via combustion synthesis from aluminum nitrate nonahydrate using asparagine as a fuel. Equivalence ratio of fuel and oxidizer, φ, on product properties is investigated. Equivalence ratios used were φ=0, 5 for a fuel lean mixture, φ=1 for a stechiometric sample and φ=1, 5 for a fuel rich sample. Methods of analysis used were X-ray diffraction (XRD), infrared spectroscopy with Fourier transformation (FTIR), scanning electron microscopy (SEM) and N2 adsorption/desorption isotherms. XRD analysis showed that the heat liberated in samples during the course of the synthesis was not high enough to obtain γ-Al2O3 so additional thermal treatment of samples was necessary. DTA analysis showed that in all of the as prepared samples there is considerable quantity of residual organic phase. According to SEM analyses and N2 adsorption/desorption isotherms it was determined that equivalence ration has great influence on microstructure and pore distribution of prepared γ-Al2O3.

Mikrokapsuliranjem farmaceutske djelatne tvari polimerima moguće je kontrolirati mjesto, vrijeme i koncentraciju njenog oslobađanja. Kako bi se pripravile mikrokapsule željenih profila oslobađanja potrebno je prirediti i ispitati polimere različitog sastava i svojstava, pri čemu se u posljednje vrijeme povećava interes za hidrofilno-hidrofobnim sustavima. Cilj ovog rada je sintetizirati kopolimere na osnovi metakrilata za oblaganje i kontrolirano oslobađanje lijekova te odrediti njihova svojstva: prosječne sastave kopolimera, raspodjelu i prosjeke molekulskih masa, toplinske fazne prijelaze i viskoznost polimernih otopina. Radikalskom kopolimerizacijom u otapalu toluenu ili butanolu sintetizirani su kopolimeri metil-metakrilata (M) s 2-(dimetilamino)etil-metakrilatom (A), vinil-pirolidonom (P) i vinil-kaprolaktamom (C) kao nositeljima poželjnih svojstava za oslobađanje djelatne tvari dronedaron-hidroklorida. Kopolimeri su potom pretaloženi u petroleteru i sušeni u vakuumskom sušioniku. Mikrokapsule su dobivene u sušioniku s raspršivanjem pri različitim protocima zraka za raspršivanje, sušenjem otopina kopolimera i dronedarona u masenim omjerima 1:1, 2:1 i 3:1. Dobivene mikrokapsule podvrgnute su in vitro metodi ispitivanja oslobađanja djelatne tvari. Analizom rezultata kromatografije na propusnom gelu određen je utjecaj reakcijskih uvjeta na raspodjelu i disperznost molekulskih masa. Diferencijalnom pretražnom kalorimetrijom određena su staklišta, a magnetskom rezonancijom jezgre sastav kopolimera. Ispitivanjem topljivosti kopolimera i brzine oslobađanja dronedarona ustanovljeno je da su kopolimeri M85A15 i M75A15 primjenjivi za mikrokapsuliranje dronedaron-hidroklorida, te su sintetizirani u većim količinama. Također, suspenzija kopolimera M85P15, djelatne tvari i otapala je stabilna, što taj sustav također čini potencijalno primjenjivim. SEM mikrografije su pokazale da povećanjem udjela polimera i smanjenjem protoka zraka nastaju kvalitetnije mikrokapsule pogodne morfologije i većih čestica. Povećanjem udjela polimera smanjuje se brzina oslobađanja te se približava profilu tablete Multaq.

Learning Overview: The goal of this presentation is to demonstrate preparation, characterization, and efficiency of Molecularly Imprinted Polymers (MIPs) designed to extract azo and anthraquinone dyes from complex matrices such as diesel fuel. MIPs are prepared for the Solid Phase Extraction (SPE) to be a faster, simpler, and more accurate way for the determination of the presence of these dyes in “laundered” fuel, even when they are present at very low concentrations. Impact on the Forensic Science Community: This presentation will impact the forensic science community by providing insight into how novel polymeric materials, prepared in a laboratory in an economical and fast way, and used as a sample pretreatment can improve detection of the desired analytes and thus provide valuable forensic evidence. Fuel consumption is steadily rising, which generates substantial profits for the oil industry, but also causes fuel prices to rise. Except, the economic factors, local laws, and regulations also determine the level of fuel tax, which differs from country to country and depends on its use. In Croatia, fuels are distinguished by use for transport vehicles, heating fuel, and fuel for propulsion of agricultural machines. Blue diesel, intended for use in agriculture, fishing, and aquaculture, has a taxable amount of 0.0 and is classified as a tax-reduced energy source, unlike tax-fueled diesel, for which the price is higher for even 0.4 €/L. In order to distinguish fuels depending on use and to prevent misuse, fuels are marked with a dye and a marker. The most commonly used marker in the European Union is Solvent Yellow 124 (SY124), the application of which is legally prescribed in Croatia. This marker is not visible to the naked eye, but only by extraction with hydrochloric or sulfuric acid, and the fuel is also labeled with visible colorants. Colorant used for labeling blue diesel in Croatia is Solvent Blue 35 (SB35), and Solvent Red 19 (SR19) is used for labeling heating oil. The fuel quantity is not legally prescribed, as opposed to the SY124 marker, which is added to the fuel in the amount of 6.0mg/L to 9.0mg/L. A big difference in the tax on such fuels, unlike fuel for transportation and its ever-increasing cost, leads to misuse. The illegal practice of removing fuel differentiation components and reselling it at a higher price is called fuel “laundering.” Fuel “laundering” occurs by adsorption of markers and colorants from fuel with widely available materials and chemicals. Losses for the state are measured in the millions. Except for the state, users of such fuel are also damaged, and the substantial damage is made to the environment because of the waste, which is disposed without proper care. As marker SY124 is not noticeable in fuel to the naked eye, intense work is conducted on the development of analytical procedures for its detection, especially in “laundered” fuel where its concentrations are extremely low. In addition to the SY124 marker, it is also important to prove the presence of blue and red dyes such as SB35 and SR19. For this purpose, MIP syntheses were performed using 4- vinylpyridine, methacrylic acid, or hydroxyethyl methacrylate as functional monomers, ethylene glycol dimethacrylate as a crosslinker, 2, 2′-Azobis(2-methylpropionitrile) (AIBN) as an initiator, and acetonitrile as a porogen. Template molecules were dyes SY124, SR19, and SB35 or combinations thereof. Various methods such as Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), the Brunauer-Emmett-Teller surface analysis method, and Evolved Gas AnalysisMass Spectrometry (EGA-MS) have been used to characterize the MIPs. The efficiency of the prepared printing polymers was monitored by Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) and compared to commercially available SPE columns. The obtained results indicate that MIPs have a possible application in the daily problem of fuel “laundering.”

U farmaceutskoj industriji pelete se mogu definirati kao sferične čestice proizvedene aglomeriranjem sitnih prašaka ili granula djelatnih i pomoćnih tvari upotrebom odgovarajuće tehnologije. Istraživanje peleta potaknuto je njihovim terapeutskim i tehnološkim prednostima u odnosu na konvencionalne dozirne oblike što je posljedica njihove višečestične prirode. Najčešće korištena tehnika peletiranja, ekstrudiranje i sferoniziranje, ima za cilj proizvesti pelete s uklopljenom djelatnom tvari kao i inertne pelete na koje se različitim postupcima nanosi djelatna tvar. Kako bi se kontroliralo oslobađanje djelatne tvari iz peleta one se često oblažu. Svojstva peleta znatno ovise o načinu pripreme, procesnim uvjetima, postupku sušenja i komponentama koje čine formulaciju. U ovom radu istraživanje je provedeno u nekoliko koraka te se sastoji od priprave peleta, njihove karakterizacije, nanošenja djelatne tvari i određivanja djelotvornosti ugradnje. Pripremljene su pelete mikrokristalne celuloze u kojima je dodatkom NaCl postignuta zadovoljavajuća poroznost. Dronedaron- hidroklorid u obliku nanosuspenzije nanesen je na pelete vakuumskom impregnacijom nakon čega su pelete obložene hidroksipropil-metil- celulozom uz dodatak bojila kako bi se vizualizirala obloga. In vitro ispitivanjem dobiveni su profili oslobađanja djelatne tvari iz peleta te su opisani odgovarajućim kinetičkim modelom. Cilj ovog rada bio je proizvesti pelete i ispitati njihov potencijal kao nosača djelatne tvari dronedaron- hidroklorida. Povećanje sadržaja nastojalo se postići pripremom djelatne tvari u obliku nanosuspenzije. Smanjenje veličine čestica djelatne tvari do nanometarskih dimenzija može značajno povećati njenu bioraspoloživost.

Filtracija je separacijski proces u kojem se čvrsta faza odvaja od kapljevine pomoću nekog filtarskog sredstva. Tok kapljevine kroz porozni sloj ostvaruje se razlikom tlakova s jedne i druge strane filtarskog sredstva (slika 1) – pokretačkom silom. Kapljevina koja prolazi kroz filtarsko sredstvo naziva se filtrat.

INTRODUCTION Fused deposition modeling (FDM) is an extrusion-based 3D printing technique easily accessible, versatile, low-cost and shows good potential for fabrication of single-unit dosage forms [1]. FDM allows variation of the type, dose, and distribution of the active ingredient as well as the size, shape, geometry, and density of the final product [2]. Because of the increasing interest for FDM in the pharmaceutical research area, the development and fabrication of filaments with active ingredient have become very important. Widely used technique for incorporating the active ingredient into the filament is hot-melt extrusion (HME). The aim of this paper is to produce filaments containing active ingredient and 3D printing of the tablets using FDM technology. MATERIALS AND METHODS Mixtures of dronedarone hydrochloride (DNR), poly(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA) filament in various proportions were used. The mixtures are prepared as a mixture of powders and as a solid dispersion. Melt flow rate of mixtures and thermogravimetric analysis of DNR were performed. The filaments were produced by HME. Diameter of prepared filaments was measured and swelling test was performed. Thermal properties of filaments and prepared mixtures were examined using differential scanning calorimetry. Prepared filaments were used for 3D printing of tablets by FDM. An in vitro drug release assay was performed from the obtained tablets. The content of dronedarone in filaments and tablets was determined using UV/Vis spectrophotometry. RESULTS The filament prepared from a solid dispersion containing 10 % PEG has the most straightforward structure ; it shows the slightest deviation from the target filament diameter (1.75 mm). The compact structure of the tablet obtained from the filament contributes to a uniform in vitro release of the DNR from matrix during 24 h. It also shows the slightest deviation from the targeted DNR content in the tablet. CONCLUSION According to all observed properties, a blend containing 10% PEG, 10% DNR and 80% PVA filament is most appropriate for HME and FDM tablet printing.

Istraživanje peleta kao nosača lijekova potaknuto je njihovim prednostima, terapeutskim i tehnološkim. Višejedinični dozirni oblici ili sustavi za primjenu lijeka koji se sastoje od skupa čestica, imaju mnogo prednosti u odnosu na monolitne dozirne oblike, poput predvidivog oslobađanja lijeka i povećane bioraspoloživosti. Tradicionalna priprema peleta kao dozirnog oblika podrazumijeva pripremu mješavine pomoćne i djelatne tvari koja se potom ekstrudira. Toplinski osjetljive djelatne tvari u takvim se procesima podvrgavaju višim temperaturama te može doći do njihove degradacije. Zbog toga su u okviru ovog istraživanja pripremljene porozne pelete te je na njih naknadno nanesena djelatna tvar. Snimanjem dušikovih adsorpcijsko-desorpcijskih izotermi određena je specifična površina, raspodjela veličina pora i srednji promjer pora u peletama. Djelatna tvar nanesena je na pelete vakuumskom impregnacijom i potapanjem u otopini. Utvrđena je djelotvornost nanošenja djelatne tvari, a potom je ispitano njezino in vitro oslobađanje. Profili oslobađanja opisani su su Peppas- Sahlinovim modelom, a dobiveni parametri modela pokazuju da je dominirajući mehanizam oslobađanja difuzija. Rezultati pokazuju da ispitivane pelete imaju potencijal kao nosači lijeka.